added a bscan extension

python_app/gui/app_window.py

@@ -274,7 +274,7 @@ class AppWindow(
 
     def _init_history_state(self) -> None:
         """Initialize runtime history buffers and render-cache state."""
-        bscan_history_limit = self._history_limit_from_config()
+        bscan_cpp_replay_window = self._cpp_bscan_replay_window_from_config()
         save_history_limit = self._save_history_limit_from_config()
         self._raw_history: deque[SweepCollection] = deque(maxlen=save_history_limit)
         self._pre_history: deque[SweepCollection] = deque(maxlen=save_history_limit)
@@ -282,7 +282,7 @@ class AppWindow(
 
         # 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 = bscan_history_limit
+        self._bscan_cpp_replay_window = bscan_cpp_replay_window
         self._bscan_history_by_combo = {}
         self._bscan_depth_axis_by_combo = {}
         self._bscan_history_floor_collection_id = 0
@@ -305,9 +305,9 @@ class AppWindow(
         self._active_processing_mode = "pass_through"
         self._radar_limits: dict[str, float | int] | None = None
 
-    def _history_limit_from_config(self) -> int:
-        """Return B-scan render history limit derived from configured ring capacities."""
-        return self._history_limit_for_config(self._defaults_config)
+    def _cpp_bscan_replay_window_from_config(self) -> int:
+        """Return the C++ B-scan replay window for the active config."""
+        return self._cpp_bscan_replay_window_for_config(self._defaults_config)
 
     def _save_history_limit_from_config(self) -> int:
         """Return maxlen for GUI snapshot-save deques (independent of ring capacities)."""