little refactoring done

python_app/gui/app_window.py

@@ -1,4 +1,8 @@
-"""Main GUI window composed from focused mixins."""
+"""Main GUI composition root.
+
+This module wires UI/controller mixins together and owns application-level
+state shared across them (runtime services, readers, history buffers, timer).
+"""
 
 from __future__ import annotations
 
@@ -35,28 +39,50 @@ class AppWindow(
     AppWindowSnapshotMixin,
     QMainWindow,
 ):
-    """Top-level application window coordinating UI and acquisition runtime."""
+    """Top-level window coordinating GUI state and acquisition runtime."""
 
     def __init__(self, project_root: Path) -> None:
-        """Initialize application state, services, UI, and polling timer."""
+        """Initialize all app subsystems in deterministic order."""
         super().__init__()
+
+        self._init_paths_and_defaults(project_root)
+        self._init_runtime_services()
+        self._init_reader_handles()
+        self._init_preprocess_state()
+        self._init_capture_state()
+        self._init_history_state()
+        self._init_runtime_limits()
+        self._init_polling_timer()
+        self._bootstrap_ui_runtime()
+
+    def _init_paths_and_defaults(self, project_root: Path) -> None:
+        """Initialize project paths and baseline run configuration."""
         self._project_root = project_root
         self._defaults_config_path = project_root / "run_config.json"
         self._defaults_config = RunConfigModel.load_from_path(self._defaults_config_path)
 
-        self._store = NpzStore(project_root / "python_app/data")
-        self._config_writer = ConfigWriter(project_root / "python_app/runtime")
-        self._supervisor = ProcessSupervisor(project_root)
-        self._live_config_writer = ProcessingLiveConfigWriter(project_root / "python_app/runtime/processing_live.json")
+    def _init_runtime_services(self) -> None:
+        """Initialize long-lived service objects used by mixins."""
+        runtime_dir = self._project_root / "python_app/runtime"
+        self._store = NpzStore(self._project_root / "python_app/data")
+        self._config_writer = ConfigWriter(runtime_dir)
+        self._supervisor = ProcessSupervisor(self._project_root)
+        self._live_config_writer = ProcessingLiveConfigWriter(runtime_dir / "processing_live.json")
 
+    def _init_reader_handles(self) -> None:
+        """Initialize SHM readers as detached (not connected) handles."""
         self._raw_reader: ShmRingReader | None = None
         self._pre_reader: ShmRingReader | None = None
         self._result_reader: ShmRingReader | None = None
 
+    def _init_preprocess_state(self) -> None:
+        """Initialize preprocessing dialog and selected set names."""
         self._preprocess_dialog: PreprocessDialog | None = None
         self._selected_calibration_set = str(self._defaults_config.preprocess.calibration_set)
         self._selected_reference_set = str(self._defaults_config.preprocess.reference_set)
 
+    def _init_capture_state(self) -> None:
+        """Initialize one-shot capture and sequence-control flags."""
         self._capture_session: SequentialCaptureSession | None = None
         self._resume_pipeline_after_capture = False
         self._single_capture_active = False
@@ -64,19 +90,16 @@ class AppWindow(
         self._single_capture_seen_raw = False
         self._single_capture_target_collection_id: int | None = None
 
-        self._raw_history: deque[SweepCollection] = deque(maxlen=512)
-        self._pre_history: deque[SweepCollection] = deque(maxlen=512)
-        result_history_limit = max(
-            1,
-            min(
-                int(self._defaults_config.rings.preprocessed.capacity),
-                int(self._defaults_config.rings.results.capacity),
-                50,
-            ),
-        )
-        self._result_history: deque[ResultCollection] = deque(maxlen=result_history_limit)
+    def _init_history_state(self) -> None:
+        """Initialize runtime history buffers and render-cache state."""
+        history_limit = self._history_limit_from_config()
+        self._raw_history: deque[SweepCollection] = deque(maxlen=history_limit)
+        self._pre_history: deque[SweepCollection] = deque(maxlen=history_limit)
+        self._result_history: deque[ResultCollection] = deque(maxlen=history_limit)
+
+        # Sequence id must survive GUI restarts so history commands stay monotonic.
         self._history_command_seq = self._load_history_command_seq(self._live_config_writer.path)
-        self._bscan_history_limit = result_history_limit
+        self._bscan_history_limit = history_limit
         self._bscan_history_by_combo = {}
         self._bscan_depth_axis_by_combo = {}
         self._bscan_history_floor_collection_id = 0
@@ -85,22 +108,43 @@ class AppWindow(
         self._history_run_signature = None
         self._radar_limits: dict[str, float | int] | None = None
 
+    def _history_limit_from_config(self) -> int:
+        """Return unified GUI history limit derived from configured ring capacities."""
+        return max(
+            1,
+            min(
+                int(self._defaults_config.rings.raw_tap.capacity),
+                int(self._defaults_config.rings.preprocessed_tap.capacity),
+                int(self._defaults_config.rings.results.capacity),
+            ),
+        )
+
+    def _init_runtime_limits(self) -> None:
+        """Initialize read/drain loop limits used by polling and snapshot code."""
         self._max_pop_per_poll = 256
         self._max_pop_per_snapshot_drain = 4096
 
+    def _init_polling_timer(self) -> None:
+        """Create periodic timer that polls SHM rings for new data."""
         self._timer = QTimer(self)
         self._timer.setInterval(50)
         self._timer.timeout.connect(self._poll_rings)
 
+    def _bootstrap_ui_runtime(self) -> None:
+        """Build UI and apply initial runtime-bound state after widgets exist."""
         self._build_ui()
         self._refresh_preprocess_summary_labels()
-        if self._radar_mode.currentText() == "native":
-            self._refresh_radar_limits_from_device()
-        else:
-            self._apply_radar_limits_to_ui(None)
+        self._apply_initial_radar_limits()
         self._write_live_processing_config()
         self._timer.start()
 
+    def _apply_initial_radar_limits(self) -> None:
+        """Apply startup radar-limits strategy according to selected radar mode."""
+        if self._radar_mode.currentText() == "native":
+            self._refresh_radar_limits_from_device()
+            return
+        self._apply_radar_limits_to_ui(None)
+
     def _log(self, text: str) -> None:
         """Append a line to the runtime log panel."""
         self._log_box.appendPlainText(text)
@@ -111,6 +155,7 @@ class AppWindow(
         try:
             payload = json.loads(config_path.read_text(encoding="utf-8"))
         except Exception:  # noqa: BLE001
+            # Missing or malformed file should not block startup.
             return 0
 
         raw_value = payload.get("history_command_seq", 0)
@@ -129,8 +174,11 @@ class AppWindow(
         """Ensure workers and dialogs are closed before window destruction."""
         try:
             self._resume_pipeline_after_capture = False
+            # 1) Abort active capture first (releases exclusive hardware resources).
             self._abort_capture_sequence(resume_pipeline=False)
+            # 2) Stop all managed processes/readers.
             self._stop_all_processes()
+            # 3) Close auxiliary dialog windows.
             if self._preprocess_dialog is not None:
                 self._preprocess_dialog.close()
         finally:

python_app/gui/controllers/app_window_config_mixin.py

@@ -179,12 +179,12 @@ class AppWindowConfigMixin:
             if self._result_history:
                 self._sync_bscan_history_from_results()
             if not self._draw_bscan_heatmap_from_history():
-                self._plot.clear()
+                self._bscan_plot.clear()
             return
         if self._result_history:
             self._draw_results(self._result_history[-1])
             return
-        self._plot.clear()
+        self._bscan_plot.clear()
         self._clear_trace_plots()
 
     def _on_radar_identity_changed(self, *_args) -> None:
@@ -317,6 +317,16 @@ class AppWindowConfigMixin:
 
     def _sync_bscan_frequency_limits_with_radar(self) -> bool:
         """Synchronize B-scan start/stop MHz widget ranges with radar sweep bounds."""
+        required_widgets = (
+            "_start_hz_input",
+            "_stop_hz_input",
+            "_bscan_start_freq_mhz",
+            "_bscan_stop_freq_mhz",
+        )
+        if not all(hasattr(self, widget_name) for widget_name in required_widgets):
+            # Processing callbacks can fire while UI groups are still being built.
+            return False
+
         try:
             radar_start_hz = float(self._start_hz_input.text().strip())
             radar_stop_hz = float(self._stop_hz_input.text().strip())

python_app/gui/controllers/app_window_plot_mixin.py

@@ -59,6 +59,29 @@ class AppWindowPlotMixin:
         """Clear pass-through magnitude and phase plots."""
         self._trace_magnitude_plot.clear()
         self._trace_phase_plot.clear()
+        self._clear_trace_legends()
+        self._trace_magnitude_curves.clear()
+        self._trace_phase_curves.clear()
+
+    def _clear_trace_legends(self) -> None:
+        """Remove trace plot legends to avoid stale combo-color mappings."""
+        mag_legend = self._trace_magnitude_legend
+        if mag_legend is not None:
+            try:
+                self._trace_magnitude_plot.getPlotItem().removeItem(mag_legend)
+            except Exception:  # noqa: BLE001
+                pass
+            self._trace_magnitude_legend = None
+        self._trace_magnitude_legend_combo_keys.clear()
+
+        phase_legend = self._trace_phase_legend
+        if phase_legend is not None:
+            try:
+                self._trace_phase_plot.getPlotItem().removeItem(phase_legend)
+            except Exception:  # noqa: BLE001
+                pass
+            self._trace_phase_legend = None
+        self._trace_phase_legend_combo_keys.clear()
 
     def _draw_trace_lines(self, collection: ResultCollection) -> bool:
         """Draw result payload traces as stacked magnitude/phase plots."""
@@ -69,8 +92,8 @@ class AppWindowPlotMixin:
 
         magnitude_plot.setVisible(show_magnitude)
         phase_plot.setVisible(show_phase)
-        self._clear_trace_plots()
         if not show_magnitude and not show_phase:
+            self._clear_trace_plots()
             return False
 
         if show_magnitude:
@@ -103,44 +126,90 @@ class AppWindowPlotMixin:
             "#1982c4",
         ]
 
-        color_index = 0
+        combo_colors: dict[tuple[int, int], str] = {}
+        legend_source_magnitude: dict[tuple[int, int], pg.PlotCurveItem] = {}
+        legend_source_phase: dict[tuple[int, int], pg.PlotCurveItem] = {}
+        active_magnitude_keys: set[tuple[int, int, int, str]] = set()
+        active_phase_keys: set[tuple[int, int, int, str]] = set()
         has_data = False
         x_min = np.inf
         x_max = -np.inf
         for block in collection.blocks:
-            for payload in block.payloads:
+            combo_key = (int(block.combo.input_pos), int(block.combo.output_pos))
+            if combo_key not in combo_colors:
+                combo_colors[combo_key] = palette[len(combo_colors) % len(palette)]
+            color = combo_colors[combo_key]
+            combo_label = f"in{combo_key[0]}/out{combo_key[1]}"
+
+            for payload_index, payload in enumerate(block.payloads):
                 if payload.kind != 1 or payload.trace.size == 0:
                     continue
                 if payload.frequency_hz.size == 0 or payload.frequency_hz.size != payload.trace.size:
                     continue
+                curve_key = (
+                    combo_key[0],
+                    combo_key[1],
+                    int(payload_index),
+                    str(payload.processing_name),
+                )
 
                 local_x_min = float(np.min(payload.frequency_hz))
                 local_x_max = float(np.max(payload.frequency_hz))
                 x_min = min(x_min, local_x_min)
                 x_max = max(x_max, local_x_max)
-                color = palette[color_index % len(palette)]
 
                 if show_magnitude:
                     magnitude_values = 20.0 * np.log10(np.maximum(np.abs(payload.trace), 1e-12))
-                    magnitude_curve = pg.PlotCurveItem(
-                        payload.frequency_hz,
-                        magnitude_values,
-                        pen=pg.mkPen(color, width=1.4),
-                    )
+                    active_magnitude_keys.add(curve_key)
+                    magnitude_curve = self._trace_magnitude_curves.get(curve_key)
+                    if magnitude_curve is None:
+                        magnitude_curve = pg.PlotCurveItem(pen=pg.mkPen(color, width=1.4))
+                        self._trace_magnitude_curves[curve_key] = magnitude_curve
                         magnitude_plot.addItem(magnitude_curve)
+                    else:
+                        magnitude_curve.setPen(pg.mkPen(color, width=1.4))
+                    magnitude_curve.setData(payload.frequency_hz, magnitude_values)
+                    legend_source_magnitude.setdefault(combo_key, magnitude_curve)
                     has_data = True
 
                 if show_phase:
-                    phase_values = np.degrees(np.angle(payload.trace))
-                    phase_curve = pg.PlotCurveItem(
-                        payload.frequency_hz,
-                        phase_values,
-                        pen=pg.mkPen(color, width=1.2, style=Qt.PenStyle.DashLine),
-                    )
+                    active_phase_keys.add(curve_key)
+                    phase_curve = self._trace_phase_curves.get(curve_key)
+                    if phase_curve is None:
+                        phase_curve = pg.PlotCurveItem(pen=pg.mkPen(color, width=1.2))
+                        self._trace_phase_curves[curve_key] = phase_curve
                         phase_plot.addItem(phase_curve)
+                    else:
+                        phase_curve.setPen(pg.mkPen(color, width=1.2))
+                    phase_x, phase_values = self._phase_display_arrays(payload.frequency_hz, payload.trace)
+                    phase_curve.setData(phase_x, phase_values)
+                    legend_source_phase.setdefault(combo_key, phase_curve)
                     has_data = True
 
-                color_index += 1
+        if show_magnitude:
+            self._remove_inactive_trace_curves(
+                plot=magnitude_plot,
+                cache=self._trace_magnitude_curves,
+                active_keys=active_magnitude_keys,
+            )
+        else:
+            self._remove_all_trace_curves(plot=magnitude_plot, cache=self._trace_magnitude_curves)
+
+        if show_phase:
+            self._remove_inactive_trace_curves(
+                plot=phase_plot,
+                cache=self._trace_phase_curves,
+                active_keys=active_phase_keys,
+            )
+        else:
+            self._remove_all_trace_curves(plot=phase_plot, cache=self._trace_phase_curves)
+
+        self._sync_trace_legends(
+            show_magnitude=show_magnitude,
+            show_phase=show_phase,
+            magnitude_sources=legend_source_magnitude,
+            phase_sources=legend_source_phase,
+        )
 
         if has_data:
             if np.isfinite(x_min) and np.isfinite(x_max):
@@ -152,6 +221,105 @@ class AppWindowPlotMixin:
                 phase_plot.setYRange(-180.0, 180.0, padding=0.02)
         return has_data
 
+    @staticmethod
+    def _remove_inactive_trace_curves(
+        *,
+        plot: pg.PlotWidget,
+        cache: dict[tuple[int, int, int, str], pg.PlotCurveItem],
+        active_keys: set[tuple[int, int, int, str]],
+    ) -> None:
+        """Delete curve items no longer present in latest result collection."""
+        for key in list(cache.keys()):
+            if key in active_keys:
+                continue
+            curve = cache.pop(key)
+            plot.removeItem(curve)
+
+    @staticmethod
+    def _remove_all_trace_curves(
+        *,
+        plot: pg.PlotWidget,
+        cache: dict[tuple[int, int, int, str], pg.PlotCurveItem],
+    ) -> None:
+        """Delete all cached curves from selected plot."""
+        for curve in cache.values():
+            plot.removeItem(curve)
+        cache.clear()
+
+    def _phase_display_arrays(self, frequency_hz: np.ndarray, trace: np.ndarray) -> tuple[np.ndarray, np.ndarray]:
+        """Return phase display arrays with decimation for faster rendering."""
+        max_points = int(getattr(self, "_trace_phase_render_max_points", 1200))
+        if max_points > 0 and trace.size > max_points:
+            step = max(1, int(np.ceil(trace.size / max_points)))
+            frequency_hz = frequency_hz[::step]
+            trace = trace[::step]
+        phase_values = np.arctan2(trace.imag, trace.real) * (180.0 / np.pi)
+        return frequency_hz, phase_values
+
+    def _sync_trace_legends(
+        self,
+        *,
+        show_magnitude: bool,
+        show_phase: bool,
+        magnitude_sources: dict[tuple[int, int], pg.PlotCurveItem],
+        phase_sources: dict[tuple[int, int], pg.PlotCurveItem],
+    ) -> None:
+        """Rebuild legends only when active combo set changes."""
+        self._sync_single_trace_legend(
+            show=show_magnitude,
+            plot=self._trace_magnitude_plot,
+            legend_attr="_trace_magnitude_legend",
+            legend_keys_attr="_trace_magnitude_legend_combo_keys",
+            sources=magnitude_sources,
+        )
+        self._sync_single_trace_legend(
+            show=show_phase,
+            plot=self._trace_phase_plot,
+            legend_attr="_trace_phase_legend",
+            legend_keys_attr="_trace_phase_legend_combo_keys",
+            sources=phase_sources,
+        )
+
+    def _sync_single_trace_legend(
+        self,
+        *,
+        show: bool,
+        plot: pg.PlotWidget,
+        legend_attr: str,
+        legend_keys_attr: str,
+        sources: dict[tuple[int, int], pg.PlotCurveItem],
+    ) -> None:
+        """Rebuild one legend from provided combo->curve mapping when needed."""
+        legend = getattr(self, legend_attr)
+        existing_keys = getattr(self, legend_keys_attr)
+        active_keys = set(sources.keys())
+        if not show or not active_keys:
+            if legend is not None:
+                try:
+                    plot.getPlotItem().removeItem(legend)
+                except Exception:  # noqa: BLE001
+                    pass
+            setattr(self, legend_attr, None)
+            existing_keys.clear()
+            return
+
+        if legend is not None and existing_keys == active_keys:
+            return
+
+        if legend is not None:
+            try:
+                plot.getPlotItem().removeItem(legend)
+            except Exception:  # noqa: BLE001
+                pass
+
+        legend = plot.addLegend(offset=(8, 8))
+        for combo_key in sorted(active_keys):
+            curve = sources[combo_key]
+            legend.addItem(curve, f"in{combo_key[0]}/out{combo_key[1]}")
+        setattr(self, legend_attr, legend)
+        existing_keys.clear()
+        existing_keys.update(active_keys)
+
     def _draw_bscan_heatmap(self, _collection: ResultCollection) -> bool:
         """Draw B-scan image rebuilt from processed result history."""
         self._disable_phase_axis()
@@ -189,18 +357,18 @@ class AppWindowPlotMixin:
         image_item.setLookupTable(self._bscan_lookup_table(axis_mode))
         image_item.setLevels(self._bscan_levels(sweeps, axis_mode))
 
-        self._plot.clear()
-        view_box = self._plot.getViewBox()
+        self._bscan_plot.clear()
+        view_box = self._bscan_plot.getViewBox()
         view_box.invertY(True)
         view_box.enableAutoRange(x=False, y=False)
-        self._plot.getPlotItem().showAxis("left", show=True)
-        self._plot.getPlotItem().showAxis("bottom", show=True)
-        self._plot.setLabel("bottom", "Sweep #")
-        self._plot.setLabel("left", "Depth", units="m")
-        self._plot.addItem(image_item)
-        self._plot.setXRange(x_min, x_max, padding=0.02)
-        self._plot.setYRange(depth_min, depth_max, padding=0.02)
-        self._plot.setTitle(f"B-scan in{display_key[0]}/out{display_key[1]} | sweeps={sweep_count}")
+        self._bscan_plot.getPlotItem().showAxis("left", show=True)
+        self._bscan_plot.getPlotItem().showAxis("bottom", show=True)
+        self._bscan_plot.setLabel("bottom", "Sweep #")
+        self._bscan_plot.setLabel("left", "Depth", units="m")
+        self._bscan_plot.addItem(image_item)
+        self._bscan_plot.setXRange(x_min, x_max, padding=0.02)
+        self._bscan_plot.setYRange(depth_min, depth_max, padding=0.02)
+        self._bscan_plot.setTitle(f"B-scan in{display_key[0]}/out{display_key[1]} | sweeps={sweep_count}")
         return True
 
     def _sync_bscan_history_from_results(self) -> None:
@@ -284,7 +452,7 @@ class AppWindowPlotMixin:
 
     def _ensure_phase_view_box(self) -> pg.ViewBox:
         """Create or return secondary right-axis ViewBox for phase curves."""
-        plot_item = self._plot.getPlotItem()
+        plot_item = self._bscan_plot.getPlotItem()
         phase_view_box = self._phase_viewbox
         if phase_view_box is None:
             phase_view_box = pg.ViewBox()
@@ -301,7 +469,7 @@ class AppWindowPlotMixin:
         phase_view_box = self._phase_viewbox
         if phase_view_box is None:
             return
-        plot_item = self._plot.getPlotItem()
+        plot_item = self._bscan_plot.getPlotItem()
         phase_view_box.setGeometry(plot_item.vb.sceneBoundingRect())
         phase_view_box.linkedViewChanged(plot_item.vb, phase_view_box.XAxis)
 
@@ -358,6 +526,9 @@ class AppWindowPlotMixin:
                 pen=pg.mkPen("#ffd166", width=1.8),
             )
             magnitude_plot.addItem(magnitude_curve)
+            self._trace_magnitude_curves[
+                (int(trace.combo.input_pos), int(trace.combo.output_pos), 0, "__single_trace__")
+            ] = magnitude_curve
 
         if show_phase:
             phase_deg = np.degrees(np.angle(trace.s21))
@@ -367,6 +538,9 @@ class AppWindowPlotMixin:
                 pen=pg.mkPen("#80ed99", width=1.4, style=Qt.PenStyle.DashLine),
             )
             phase_plot.addItem(phase_curve)
+            self._trace_phase_curves[
+                (int(trace.combo.input_pos), int(trace.combo.output_pos), 0, "__single_trace__")
+            ] = phase_curve
             phase_plot.setYRange(-180.0, 180.0, padding=0.02)
 
         if np.size(trace.frequency_hz) > 1:

python_app/gui/controllers/app_window_ui_mixin.py

@@ -1,4 +1,11 @@
-"""UI construction mixin for the main radar control window."""
+"""UI construction mixin for the main radar control window.
+
+Layout is intentionally split into two independent plot surfaces:
+- single `PlotWidget` for B-scan heatmap rendering;
+- stacked magnitude/phase `PlotWidget`s for pass-through traces.
+
+`_set_plot_mode()` switches between these surfaces via `QStackedWidget`.
+"""
 
 from __future__ import annotations
 
@@ -29,10 +36,21 @@ from python_app.gui.controllers.sections import (
 
 
 class AppWindowUiMixin:
-    """Builds and wires all static UI widgets."""
+    """Build and wire all static widgets used by :class:`AppWindow`.
+
+    This mixin only creates UI objects and connects lightweight UI signals.
+    Runtime logic (pipeline start/stop, polling, drawing, snapshot saving)
+    is implemented in other mixins.
+    """
 
     def _build_ui(self) -> None:
-        """Build main window widgets, plot area, and settings panel."""
+        """Build complete main-window layout.
+
+        High-level structure:
+        1. Left: plot stack (`B-scan` page + `trace magnitude/phase` page).
+        2. Middle: narrow toggle button to collapse/expand settings.
+        3. Right: scrollable settings panel + status/history + runtime log.
+        """
         self.setWindowTitle("Radar System Control")
         root = QWidget(self)
         self.setCentralWidget(root)
@@ -41,15 +59,37 @@ class AppWindowUiMixin:
         layout.setContentsMargins(12, 12, 12, 12)
         layout.setSpacing(14)
 
+        self._build_plot_area(layout, root)
+        self._build_settings_toggle(layout)
+        self._build_settings_panel(layout, root)
+
+        self._toggle_settings_panel(visible=True)
+        self.resize(1650, 940)
+
+    def _build_plot_area(self, root_layout: QHBoxLayout, root: QWidget) -> None:
+        """Build left plot area with stacked B-scan and trace pages."""
+        # Plot stack holds mutually exclusive visualization surfaces.
+        # We create both upfront and only switch active page at runtime.
         self._plot_stack = QStackedWidget(root)
+        self._build_bscan_plot_page()
+        self._build_trace_plot_page()
 
-        self._plot = pg.PlotWidget(background="#0f141c")
-        self._plot.showGrid(x=True, y=True, alpha=0.2)
-        self._plot.setLabel("bottom", "Frequency", units="Hz")
-        self._plot.setLabel("left", "Magnitude", units="dB")
-        self._plot_stack.addWidget(self._plot)
+        # Default view on startup is pass-through traces.
+        self._plot_stack.setCurrentWidget(self._trace_plots_container)
+        root_layout.addWidget(self._plot_stack, stretch=11)
 
-        self._trace_plots_container = QWidget(root)
+    def _build_bscan_plot_page(self) -> None:
+        """Create B-scan page in plot stack."""
+        # B-scan surface: one PlotWidget used as canvas for ImageItem heatmap.
+        self._bscan_plot = pg.PlotWidget(background="#0f141c")
+        self._bscan_plot.showGrid(x=True, y=True, alpha=0.2)
+        self._plot_stack.addWidget(self._bscan_plot)
+
+    def _build_trace_plot_page(self) -> None:
+        """Create pass-through page with magnitude and phase plots."""
+        # Pass-through surface: container with two synchronized line plots.
+        # Upper plot shows magnitude, lower plot shows phase.
+        self._trace_plots_container = QWidget()
         trace_layout = QVBoxLayout(self._trace_plots_container)
         trace_layout.setContentsMargins(0, 0, 0, 0)
         trace_layout.setSpacing(6)
@@ -70,53 +110,40 @@ class AppWindowUiMixin:
         self._trace_phase_plot.getPlotItem().setClipToView(True)
         trace_layout.addWidget(self._trace_phase_plot, stretch=1)
 
-        self._plot_stack.addWidget(self._trace_plots_container)
-        self._plot_stack.setCurrentWidget(self._trace_plots_container)
-        layout.addWidget(self._plot_stack, stretch=11)
+        # Legends are created lazily only when trace mode draws line series.
+        self._trace_magnitude_legend = None
+        self._trace_phase_legend = None
+        self._trace_magnitude_legend_combo_keys = set()
+        self._trace_phase_legend_combo_keys = set()
+        self._trace_magnitude_curves = {}
+        self._trace_phase_curves = {}
+        self._trace_phase_render_max_points = 400
 
+        self._plot_stack.addWidget(self._trace_plots_container)
+
+    def _build_settings_toggle(self, root_layout: QHBoxLayout) -> None:
+        """Create narrow button used to collapse or show settings panel."""
         self._settings_toggle_button = QPushButton("<")
         self._settings_toggle_button.setObjectName("settingsToggleButton")
         self._settings_toggle_button.setFixedWidth(26)
-        self._settings_toggle_button.clicked.connect(self._toggle_settings_panel)
-        layout.addWidget(self._settings_toggle_button, stretch=0)
+        self._settings_toggle_button.clicked.connect(lambda: self._toggle_settings_panel())
+        root_layout.addWidget(self._settings_toggle_button, stretch=0)
 
+    def _build_settings_panel(self, root_layout: QHBoxLayout, root: QWidget) -> None:
+        """Build right settings panel with controls, status labels, and log."""
         self._settings_panel = QWidget(root)
         self._settings_panel.setMinimumWidth(659)
         right_layout = QVBoxLayout(self._settings_panel)
         right_layout.setContentsMargins(0, 0, 0, 0)
         right_layout.setSpacing(10)
 
-        # Build log widget early so error handlers can safely write during UI construction.
+        # Build log early so `_show_error()` can append text even during
+        # subsequent group construction if something fails.
         self._log_box = QPlainTextEdit(self._settings_panel)
         self._log_box.setReadOnly(True)
         self._log_box.setMinimumHeight(170)
 
-        pipeline_group = self._build_pipeline_group()
-        hardware_actions_group = self._build_hardware_actions_group()
-        data_actions_group = self._build_data_actions_group()
-        preprocess_summary_group = self._build_preprocess_summary_group()
-        radar_group = self._build_radar_group()
-        processing_group = self._build_processing_group()
-        switch_group = self._build_switch_group()
-
-        controls = QWidget(self._settings_panel)
-        controls_layout = QVBoxLayout(controls)
-        controls_layout.setContentsMargins(0, 0, 0, 0)
-        controls_layout.setSpacing(10)
-        controls_layout.addWidget(pipeline_group)
-        controls_layout.addWidget(hardware_actions_group)
-        controls_layout.addWidget(data_actions_group)
-        controls_layout.addWidget(preprocess_summary_group)
-        controls_layout.addWidget(processing_group)
-        controls_layout.addWidget(radar_group)
-        controls_layout.addWidget(switch_group)
-        controls_layout.addStretch(1)
-
-        scroll = QScrollArea(self._settings_panel)
-        scroll.setWidgetResizable(True)
-        scroll.setFrameShape(QFrame.Shape.NoFrame)
-        scroll.setWidget(controls)
-        right_layout.addWidget(scroll, stretch=1)
+        right_layout.addWidget(self._build_settings_scroll(), stretch=1)
 
         self._status_label = QLabel("Status: idle", self._settings_panel)
         self._status_label.setObjectName("statusLabel")
@@ -127,17 +154,46 @@ class AppWindowUiMixin:
         right_layout.addWidget(self._history_label)
 
         right_layout.addWidget(self._log_box, stretch=0)
+        root_layout.addWidget(self._settings_panel, stretch=8)
 
-        layout.addWidget(self._settings_panel, stretch=8)
-        self._set_settings_panel_visible(True)
-        self.resize(1650, 940)
+    def _build_settings_scroll(self) -> QScrollArea:
+        """Build scroll area with all control groups in display order."""
+        # All control groups are placed into a scroll area so right panel
+        # remains usable on smaller screens and with future extra controls.
+        controls = QWidget(self._settings_panel)
+        controls_layout = QVBoxLayout(controls)
+        controls_layout.setContentsMargins(0, 0, 0, 0)
+        controls_layout.setSpacing(10)
+        for group in self._build_control_groups():
+            controls_layout.addWidget(group)
+        controls_layout.addStretch(1)
 
-    def _toggle_settings_panel(self) -> None:
-        """Toggle settings panel visibility."""
-        self._set_settings_panel_visible(not self._settings_panel.isVisible())
+        scroll = QScrollArea(self._settings_panel)
+        scroll.setWidgetResizable(True)
+        scroll.setFrameShape(QFrame.Shape.NoFrame)
+        scroll.setWidget(controls)
+        return scroll
 
-    def _set_settings_panel_visible(self, visible: bool) -> None:
-        """Set settings panel visibility and update toggle button glyph."""
+    def _build_control_groups(self) -> list[QGroupBox]:
+        """Create all settings groups in top-to-bottom order."""
+        return [
+            build_pipeline_group(self),
+            build_hardware_actions_group(self),
+            build_data_actions_group(self),
+            build_preprocess_summary_group(self),
+            build_processing_group(self),
+            build_radar_group(self),
+            build_switch_group(self),
+        ]
+
+    def _toggle_settings_panel(self, *, visible: bool | None = None) -> None:
+        """Toggle settings panel visibility or force a specific state.
+
+        When `visible` is `None`, state is toggled.
+        When `visible` is set, panel visibility is forced to that value.
+        """
+        if visible is None:
+            visible = not self._settings_panel.isVisible()
         self._settings_panel.setVisible(visible)
         if visible:
             self._settings_toggle_button.setText(">")
@@ -147,40 +203,16 @@ class AppWindowUiMixin:
             self._settings_toggle_button.setToolTip("Show settings panel")
 
     def _set_plot_mode(self, mode: str) -> None:
-        """Switch visible plot surface based on processing mode."""
+        """Switch visible plot page according to processing mode.
+
+        `bscan`   -> show `self._bscan_plot` (single heatmap surface)
+        otherwise -> show `self._trace_plots_container` (magnitude + phase)
+        """
         if mode == "bscan":
-            self._plot_stack.setCurrentWidget(self._plot)
+            self._plot_stack.setCurrentWidget(self._bscan_plot)
             return
         self._plot_stack.setCurrentWidget(self._trace_plots_container)
 
-    def _build_pipeline_group(self) -> QGroupBox:
-        """Build pipeline controls section."""
-        return build_pipeline_group(self)
-
-    def _build_hardware_actions_group(self) -> QGroupBox:
-        """Build hardware actions section."""
-        return build_hardware_actions_group(self)
-
-    def _build_data_actions_group(self) -> QGroupBox:
-        """Build data actions section."""
-        return build_data_actions_group(self)
-
-    def _build_preprocess_summary_group(self) -> QGroupBox:
-        """Build selected preprocess sets summary section."""
-        return build_preprocess_summary_group(self)
-
-    def _build_processing_group(self) -> QGroupBox:
-        """Build processing mode section."""
-        return build_processing_group(self)
-
-    def _build_radar_group(self) -> QGroupBox:
-        """Build radar settings section."""
-        return build_radar_group(self)
-
-    def _build_switch_group(self) -> QGroupBox:
-        """Build switch settings section."""
-        return build_switch_group(self)
-
     @staticmethod
     def _set_combo_current_text(combo: QComboBox, value: str) -> None:
         """Select combo item by text, appending it when missing."""

python_app/gui/preprocess_dialog.py

@@ -6,7 +6,6 @@ from PyQt6.QtCore import pyqtSignal
 from PyQt6.QtWidgets import (
     QComboBox,
     QDialog,
-    QFormLayout,
     QGridLayout,
     QGroupBox,
     QHBoxLayout,
@@ -23,7 +22,13 @@ from python_app.models.dataset_model import TraceData
 
 
 class PreprocessDialog(QDialog):
-    """Standalone dialog for preprocessing capture workflows."""
+    """Standalone dialog for preprocessing capture workflows.
+
+    The dialog combines three concerns:
+    1. Set selection (calibration/reference).
+    2. Sequential capture controls for filling all N*M combinations.
+    3. Quick preview of the last captured trace.
+    """
 
     refresh_requested = pyqtSignal()
     selection_changed = pyqtSignal(str, str)
@@ -32,64 +37,97 @@ class PreprocessDialog(QDialog):
     abort_sequence_requested = pyqtSignal()
 
     def __init__(self, parent=None) -> None:
-        """Create dialog and build all widgets."""
+        """Initialize window metadata and compose dialog UI."""
         super().__init__(parent)
-        self.setWindowTitle("Preprocessing Setup")
-        self.resize(1040, 760)
+        self._init_window()
         self._build_ui()
 
+    def _init_window(self) -> None:
+        """Set static window properties."""
+        self.setWindowTitle("Preprocessing Setup")
+        self.resize(1040, 760)
+
     def _build_ui(self) -> None:
-        """Build dialog layout, controls, and preview plot."""
-        layout = QVBoxLayout(self)
+        """Build root dialog layout and all sections."""
+        root_layout = QVBoxLayout(self)
+        root_layout.addWidget(self._build_sets_group())
+        root_layout.addWidget(self._build_sequence_group())
+        self._build_status_line(root_layout)
+        self._build_preview_plot(root_layout)
 
-        sets_group = QGroupBox("Calibration / Reference Sets", self)
-        sets_layout = QGridLayout(sets_group)
+    def _build_sets_group(self) -> QGroupBox:
+        """Build set-management controls used for preprocessing snapshots."""
+        group = QGroupBox("Calibration / Reference Sets", self)
+        layout = QGridLayout(group)
 
-        self._set_name_input = QLineEdit("set_001", sets_group)
-        self._calibration_combo = QComboBox(sets_group)
-        self._reference_combo = QComboBox(sets_group)
+        self._set_name_input = QLineEdit("set_001", group)
+        self._calibration_combo = QComboBox(group)
+        self._reference_combo = QComboBox(group)
 
-        refresh_button = QPushButton("Refresh Sets", sets_group)
+        refresh_button = QPushButton("Refresh Sets", group)
         refresh_button.clicked.connect(self.refresh_requested.emit)
 
         self._calibration_combo.currentTextChanged.connect(self._emit_selection_changed)
         self._reference_combo.currentTextChanged.connect(self._emit_selection_changed)
 
-        sets_layout.addWidget(QLabel("Set name"), 0, 0)
-        sets_layout.addWidget(self._set_name_input, 0, 1)
-        sets_layout.addWidget(refresh_button, 0, 2)
+        layout.addWidget(QLabel("Set name"), 0, 0)
+        layout.addWidget(self._set_name_input, 0, 1)
+        layout.addWidget(refresh_button, 0, 2)
 
-        sets_layout.addWidget(QLabel("Calibration set"), 1, 0)
-        sets_layout.addWidget(self._calibration_combo, 1, 1, 1, 2)
+        layout.addWidget(QLabel("Calibration set"), 1, 0)
+        layout.addWidget(self._calibration_combo, 1, 1, 1, 2)
 
-        sets_layout.addWidget(QLabel("Reference set"), 2, 0)
-        sets_layout.addWidget(self._reference_combo, 2, 1, 1, 2)
+        layout.addWidget(QLabel("Reference set"), 2, 0)
+        layout.addWidget(self._reference_combo, 2, 1, 1, 2)
+        return group
 
-        layout.addWidget(sets_group)
+    def _build_sequence_group(self) -> QGroupBox:
+        """Build sequential-capture controls and capture log."""
+        group = QGroupBox("Sequential Capture (Fill Full N*M)", self)
+        layout = QGridLayout(group)
 
-        sequence_group = QGroupBox("Sequential Capture (Fill Full N*M)", self)
-        sequence_layout = QGridLayout(sequence_group)
+        self._active_kind_label = QLabel("<none>", group)
+        self._progress_label = QLabel("0 / 0", group)
+        self._combo_label = QLabel("<none>", group)
 
-        self._active_kind_label = QLabel("<none>", sequence_group)
-        self._progress_label = QLabel("0 / 0", sequence_group)
-        self._combo_label = QLabel("<none>", sequence_group)
-
-        self._tx_antenna_label_input = QLineEdit(sequence_group)
-        self._rx_antenna_label_input = QLineEdit(sequence_group)
+        self._tx_antenna_label_input = QLineEdit(group)
+        self._rx_antenna_label_input = QLineEdit(group)
         self._tx_antenna_label_input.setPlaceholderText("e.g. TX_A")
         self._rx_antenna_label_input.setPlaceholderText("e.g. RX_B")
 
-        start_calibration_button = QPushButton("Start Calibration Sequence", sequence_group)
+        button_row = self._build_sequence_button_row(group)
+
+        layout.addWidget(QLabel("Active type"), 0, 0)
+        layout.addWidget(self._active_kind_label, 0, 1)
+        layout.addWidget(QLabel("Progress"), 1, 0)
+        layout.addWidget(self._progress_label, 1, 1)
+        layout.addWidget(QLabel("Current combo"), 2, 0)
+        layout.addWidget(self._combo_label, 2, 1)
+        layout.addWidget(QLabel("TX antenna label"), 3, 0)
+        layout.addWidget(self._tx_antenna_label_input, 3, 1)
+        layout.addWidget(QLabel("RX antenna label"), 4, 0)
+        layout.addWidget(self._rx_antenna_label_input, 4, 1)
+        layout.addLayout(button_row, 5, 0, 1, 2)
+
+        self._capture_log = QPlainTextEdit(group)
+        self._capture_log.setReadOnly(True)
+        self._capture_log.setPlaceholderText("Capture history per combo")
+        layout.addWidget(self._capture_log, 6, 0, 1, 2)
+        return group
+
+    def _build_sequence_button_row(self, parent: QGroupBox) -> QHBoxLayout:
+        """Build action buttons for sequence flow control."""
+        start_calibration_button = QPushButton("Start Calibration Sequence", parent)
         start_calibration_button.clicked.connect(lambda: self.start_sequence_requested.emit("calibration"))
 
-        start_reference_button = QPushButton("Start Reference Sequence", sequence_group)
+        start_reference_button = QPushButton("Start Reference Sequence", parent)
         start_reference_button.clicked.connect(lambda: self.start_sequence_requested.emit("reference"))
 
-        self._capture_next_button = QPushButton("Capture Current Combo", sequence_group)
+        self._capture_next_button = QPushButton("Capture Current Combo", parent)
         self._capture_next_button.clicked.connect(self.capture_next_requested.emit)
         self._capture_next_button.setEnabled(False)
 
-        self._abort_button = QPushButton("Abort Sequence", sequence_group)
+        self._abort_button = QPushButton("Abort Sequence", parent)
         self._abort_button.clicked.connect(self.abort_sequence_requested.emit)
         self._abort_button.setEnabled(False)
 
@@ -98,34 +136,20 @@ class PreprocessDialog(QDialog):
         button_row.addWidget(start_reference_button)
         button_row.addWidget(self._capture_next_button)
         button_row.addWidget(self._abort_button)
+        return button_row
 
-        sequence_layout.addWidget(QLabel("Active type"), 0, 0)
-        sequence_layout.addWidget(self._active_kind_label, 0, 1)
-        sequence_layout.addWidget(QLabel("Progress"), 1, 0)
-        sequence_layout.addWidget(self._progress_label, 1, 1)
-        sequence_layout.addWidget(QLabel("Current combo"), 2, 0)
-        sequence_layout.addWidget(self._combo_label, 2, 1)
-        sequence_layout.addWidget(QLabel("TX antenna label"), 3, 0)
-        sequence_layout.addWidget(self._tx_antenna_label_input, 3, 1)
-        sequence_layout.addWidget(QLabel("RX antenna label"), 4, 0)
-        sequence_layout.addWidget(self._rx_antenna_label_input, 4, 1)
-        sequence_layout.addLayout(button_row, 5, 0, 1, 2)
+    def _build_status_line(self, root_layout: QVBoxLayout) -> None:
+        """Build one-line status output for dialog operations."""
+        self._status_label = QLabel("Ready", self)
+        root_layout.addWidget(self._status_label)
 
-        self._capture_log = QPlainTextEdit(sequence_group)
-        self._capture_log.setReadOnly(True)
-        self._capture_log.setPlaceholderText("Capture history per combo")
-        sequence_layout.addWidget(self._capture_log, 6, 0, 1, 2)
-
-        layout.addWidget(sequence_group)
-
-        self._status = QLabel("Ready", self)
-        layout.addWidget(self._status)
-
-        self._plot = pg.PlotWidget(background="#101418")
-        self._plot.showGrid(x=True, y=True, alpha=0.2)
-        self._plot.setLabel("bottom", "Frequency", units="Hz")
-        self._plot.setLabel("left", "Magnitude", units="dB")
-        layout.addWidget(self._plot, stretch=1)
+    def _build_preview_plot(self, root_layout: QVBoxLayout) -> None:
+        """Build trace preview plot used after each successful capture."""
+        self._preview_plot = pg.PlotWidget(background="#101418")
+        self._preview_plot.showGrid(x=True, y=True, alpha=0.2)
+        self._preview_plot.setLabel("bottom", "Frequency", units="Hz")
+        self._preview_plot.setLabel("left", "Magnitude", units="dB")
+        root_layout.addWidget(self._preview_plot, stretch=1)
 
     def set_name(self) -> str:
         """Return requested target set name."""
@@ -220,19 +244,19 @@ class PreprocessDialog(QDialog):
 
     def set_status(self, message: str) -> None:
         """Set short human-readable status line."""
-        self._status.setText(message)
+        self._status_label.setText(message)
 
     def draw_last_trace(self, trace: TraceData, title: str) -> None:
         """Draw the latest captured sweep trace in dB scale."""
         magnitude_db = 20.0 * np.log10(np.maximum(np.abs(trace.s21), 1e-12))
-        self._plot.clear()
-        self._plot.plot(
+        self._preview_plot.clear()
+        self._preview_plot.plot(
             trace.frequency_hz,
             magnitude_db,
             pen=pg.mkPen("#4cc9f0", width=1.8),
         )
         combo = trace.combo
-        self._status.setText(
+        self._status_label.setText(
             f"{title}: input={combo.input_pos}, output={combo.output_pos}, points={trace.frequency_hz.size}"
         )
 

python_app/models/run_config_codec.py

@@ -2,12 +2,19 @@
 
 from __future__ import annotations
 
-import json
-from pathlib import Path
 from typing import Any
 
 from python_app.models.run_config_schema import ComboModel, RunConfigModel
-from python_app.models.run_config_validation import as_dict, load_ring_payload, load_switch_payload
+from python_app.models.run_config_validation import load_ring_payload, load_switch_payload
+
+
+def _as_dict(value: Any, context: str) -> dict[str, Any]:
+    """Validate payload node is object-like, treating missing values as empty object."""
+    if value is None:
+        return {}
+    if not isinstance(value, dict):
+        raise ValueError(f"{context} must be a JSON object")
+    return value
 
 
 def run_config_from_dict(payload: dict[str, Any]) -> RunConfigModel:
@@ -15,19 +22,19 @@ def run_config_from_dict(payload: dict[str, Any]) -> RunConfigModel:
     # Schema carries only minimal-safe fallbacks; operational defaults live in run_config.json.
     model = RunConfigModel()
 
-    radar_payload = as_dict(payload.get("radar"), "radar")
-    sweep_payload = as_dict(radar_payload.get("sweep"), "radar.sweep")
-    switches_payload = as_dict(payload.get("switches"), "switches")
-    port1_payload = as_dict(switches_payload.get("port1"), "switches.port1")
-    port2_payload = as_dict(switches_payload.get("port2"), "switches.port2")
-    run_payload = as_dict(payload.get("run"), "run")
-    preprocess_payload = as_dict(payload.get("preprocess"), "preprocess")
-    rings_payload = as_dict(payload.get("rings"), "rings")
-    raw_ring_payload = as_dict(rings_payload.get("raw"), "rings.raw")
-    raw_tap_ring_payload = as_dict(rings_payload.get("raw_tap"), "rings.raw_tap")
-    pre_ring_payload = as_dict(rings_payload.get("preprocessed"), "rings.preprocessed")
-    pre_tap_ring_payload = as_dict(rings_payload.get("preprocessed_tap"), "rings.preprocessed_tap")
-    result_ring_payload = as_dict(rings_payload.get("results"), "rings.results")
+    radar_payload = _as_dict(payload.get("radar"), "radar")
+    sweep_payload = _as_dict(radar_payload.get("sweep"), "radar.sweep")
+    switches_payload = _as_dict(payload.get("switches"), "switches")
+    port1_payload = _as_dict(switches_payload.get("port1"), "switches.port1")
+    port2_payload = _as_dict(switches_payload.get("port2"), "switches.port2")
+    run_payload = _as_dict(payload.get("run"), "run")
+    preprocess_payload = _as_dict(payload.get("preprocess"), "preprocess")
+    rings_payload = _as_dict(payload.get("rings"), "rings")
+    raw_ring_payload = _as_dict(rings_payload.get("raw"), "rings.raw")
+    raw_tap_ring_payload = _as_dict(rings_payload.get("raw_tap"), "rings.raw_tap")
+    pre_ring_payload = _as_dict(rings_payload.get("preprocessed"), "rings.preprocessed")
+    pre_tap_ring_payload = _as_dict(rings_payload.get("preprocessed_tap"), "rings.preprocessed_tap")
+    result_ring_payload = _as_dict(rings_payload.get("results"), "rings.results")
 
     model.radar.model = str(radar_payload.get("model", model.radar.model))
     model.radar.serial = str(radar_payload.get("serial", model.radar.serial))
@@ -71,7 +78,7 @@ def run_config_from_dict(payload: dict[str, Any]) -> RunConfigModel:
     model.combos = []
     if isinstance(combos_payload, list):
         for combo in combos_payload:
-            combo_payload = as_dict(combo, "run.combos[]")
+            combo_payload = _as_dict(combo, "run.combos[]")
             model.combos.append(
                 ComboModel(
                     input=int(combo_payload.get("input", 0)),
@@ -82,15 +89,6 @@ def run_config_from_dict(payload: dict[str, Any]) -> RunConfigModel:
     model.ensure_combos()
     return model
 
-
-def load_run_config(path: Path) -> RunConfigModel:
-    """Load JSON config from path and decode into :class:`RunConfigModel`."""
-    payload = json.loads(path.read_text(encoding="utf-8"))
-    if not isinstance(payload, dict):
-        raise ValueError(f"Config root must be JSON object: {path}")
-    return run_config_from_dict(payload)
-
-
 def run_config_to_dict(model: RunConfigModel) -> dict[str, Any]:
     """Encode :class:`RunConfigModel` to C++ pipeline-compatible JSON structure."""
     model.ensure_combos()

python_app/models/run_config_model.py

@@ -1,6 +1,6 @@
 """Facade module for run configuration schema, codec, and validation helpers."""
 
-from python_app.models.run_config_codec import load_run_config, run_config_from_dict, run_config_to_dict
+from python_app.models.run_config_codec import run_config_from_dict, run_config_to_dict
 from python_app.models.run_config_schema import (
     ComboModel,
     PreprocessModel,
@@ -13,7 +13,6 @@ from python_app.models.run_config_schema import (
     SwitchModel,
 )
 from python_app.models.run_config_validation import (
-    as_dict,
     load_ring_payload,
     load_switch_payload,
     parse_combos_from_text,
@@ -29,9 +28,7 @@ __all__ = [
     "RunConfigModel",
     "RuntimeModel",
     "SwitchModel",
-    "as_dict",
     "load_ring_payload",
-    "load_run_config",
     "load_switch_payload",
     "parse_combos_from_text",
     "run_config_from_dict",

python_app/models/run_config_schema.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 from dataclasses import dataclass, field
+import json
 from pathlib import Path
 from typing import Any
 
@@ -131,9 +132,10 @@ class RunConfigModel:
     @classmethod
     def load_from_path(cls, path: Path) -> RunConfigModel:
         """Load JSON file from disk and decode into model."""
-        from python_app.models.run_config_codec import load_run_config
-
-        return load_run_config(path)
+        payload = json.loads(path.read_text(encoding="utf-8"))
+        if not isinstance(payload, dict):
+            raise ValueError(f"Config root must be JSON object: {path}")
+        return cls.from_dict(payload)
 
     def clone(self) -> RunConfigModel:
         """Create deep copy through codec round-trip."""

python_app/models/run_config_validation.py

@@ -6,16 +6,6 @@ from typing import Any
 
 from python_app.models.run_config_schema import ComboModel, RingEndpointModel, SwitchModel
 
-
-def as_dict(value: Any, context: str) -> dict[str, Any]:
-    """Validate that a payload node is a JSON object and return it."""
-    if value is None:
-        return {}
-    if not isinstance(value, dict):
-        raise ValueError(f"{context} must be a JSON object")
-    return value
-
-
 def load_switch_payload(
     payload: dict[str, Any],
     target: SwitchModel,

run_config.json

@@ -57,27 +57,27 @@
   "rings": {
     "raw": {
       "name": "/radar_raw",
-      "capacity": 64,
+      "capacity": 50,
       "slot_size_bytes": 2097152
     },
     "raw_tap": {
       "name": "/radar_raw_tap",
-      "capacity": 64,
+      "capacity": 50,
       "slot_size_bytes": 2097152
     },
     "preprocessed": {
       "name": "/radar_preprocessed",
-      "capacity": 64,
+      "capacity": 50,
       "slot_size_bytes": 2097152
     },
     "preprocessed_tap": {
       "name": "/radar_preprocessed_tap",
-      "capacity": 64,
+      "capacity": 50,
       "slot_size_bytes": 2097152
     },
     "results": {
       "name": "/radar_results",
-      "capacity": 64,
+      "capacity": 50,
       "slot_size_bytes": 2097152
     }
   }