feat(ui): improve device session management, update data directory paths, and add session clearing functionality.

src/pygui/backend/controllers/device_controller.py

@@ -1,10 +1,4 @@
-"""QML-exposed controller for wafer device communication.
-
-Bridges DeviceService (serialcomm) to QML via @Slot methods and signals.
-All hardware operations run synchronously on the main thread (matching
-C# Form1.cs per-operation open/close pattern).  For long operations
-(erase ~15s, read up to 120s) the caller should show a loading state.
-"""
+"""QML-exposed controller for wafer device communication."""
 
 from __future__ import annotations
 
@@ -67,9 +61,8 @@ class DeviceController(QObject):
         self._operation_in_progress = False
         self._activity_log: list[str] = getattr(settings, 'activity_log', [])
         self._raw_bytes: Optional[bytes] = None
-        # Default save dir lives next to the settings file (~/Documents/isc_data/csv)
         from pathlib import Path
-        self._save_data_dir: str = getattr(settings, 'save_data_dir', str(Path.home() / "Documents" / "isc_data" / "csv"))
+        self._save_data_dir: str = getattr(settings, 'save_data_dir', "") or str(Path(self._data_dir) / "csv")
         self._last_wafer_info: dict[str, Any] = getattr(settings, 'last_wafer_info', {})
         self._last_csv_path: str = getattr(settings, 'last_csv_path', "")
         self._selected_port: str = getattr(settings, 'selected_port', "")
@@ -209,6 +202,28 @@ class DeviceController(QObject):
             self._activity_log = self._activity_log[-200:]
         self.activityLogUpdated.emit("\n".join(self._activity_log))
 
+    @Slot()
+    def clearActivityLog(self) -> None:
+        """Clear the activity log."""
+        self._activity_log.clear()
+        self.activityLogUpdated.emit("")
+        self._save_status()
+
+    @Slot()
+    def clearSession(self) -> None:
+        """Clear the current session state, allowing a clean detect."""
+        self._connection_status = "Disconnected"
+        self._selected_port = ""
+        self._last_wafer_info = {}
+        self._data_row_count = 0
+        self._data_col_count = 0
+        self._raw_bytes = None
+        self._operation_in_progress = False
+        self.detectResult.emit(None)
+        self.portsUpdated.emit(self.availablePorts)
+        self._append_log("Session refreshed/cleared")
+        self._save_status()
+
     def _set_operation_progress(self, in_progress: bool) -> None:
         """Set operation progress state and notify QML.
 
@@ -424,12 +439,10 @@ class DeviceController(QObject):
             return
 
         if not self._save_data_dir:
-            self._append_log("No save data directory set")
-            self.parsedDataReady.emit({
-                "success": False,
-                "error": "No save data directory set",
-            })
-            return
+            from pathlib import Path
+            self._save_data_dir = str(Path(self._data_dir) / "csv")
+            self._append_log(f"Auto-set save directory to: {self._save_data_dir}")
+            self._save_status()
 
         fc = family_code or (
             self._last_wafer_info.get("familyCode", "")
@@ -509,7 +522,7 @@ class DeviceController(QObject):
         self._settings.last_csv_path = self._last_csv_path
 
         # Save to disk
-        LocalSettings.save_settings(str(LocalSettings._settings_path(self._data_dir)), self._settings)
+        LocalSettings.save_settings(self._data_dir, self._settings)
 
     # ---- Helpers ----
 

src/pygui/backend/data/local_settings_model.py

@@ -52,7 +52,7 @@ class LocalSettingsModel(QObject):
             QStandardPaths.DocumentsLocation
         )
         base_dir = Path(documents_dir) if documents_dir else (Path.home() / "Documents")
-        return base_dir / "isc_data"
+        return base_dir / "ISC_DATA"
 
     def _new_defaults(self) -> dict[str, Any]:
         return {