feat: add interactive folder selection for CSV saves and stabilize cross-platform dependency locking

src/pygui/backend/controllers/device_controller.py

@@ -303,7 +303,8 @@ class DeviceController(QObject):
         """Read wafer memory in a background thread.
 
         Uses the family code and port from the last detect.
-        Emits readResult on completion, then auto-chains to parseAndSaveData.
+        Emits readResult on completion; QML prompts for the save directory
+        before calling parseAndSaveData.
         """
         if self._operation_in_progress:
             self._append_log("Already busy — ignoring read request")
@@ -350,9 +351,7 @@ class DeviceController(QObject):
             self._raw_bytes = data
             self.readResult.emit({"success": True, "bytes": len(data)})
             self._set_operation_progress(False)
-            # Auto-chain: read → parse → save (matches C# behavior).
-            # Parse runs on main thread — it's CPU-bound but bounded (~1s).
-            self.parseAndSaveData(family_code, port)
+            self._append_log("Memory read complete - choose save directory to save CSV")
             self._save_status()
             return
         self._connection_status = "Disconnected"
@@ -489,6 +488,7 @@ class DeviceController(QObject):
             return
 
         self._append_log(f"Saved CSV: {csv_path}")
+        self._last_csv_path = csv_path
 
         # Load data into the QAbstractTableModel
         self._data_model.load_data(temp_data, cols)