fix: Replace all invokeMethod calls with Qt signals for thread-safety

BUG: QMetaObject.invokeMethod with Q_ARG doesn't work properly in PyQt6
and was causing TypeError exceptions.

FIX:
- Added proper Qt signals at class level:
  * update_status_signal(str, bool, bool)
  * update_session_table_signal(object)
  * update_counters_signal()
  * enable_scan_button_signal(bool)

- Connected all signals to slot methods in initialize()
- Replaced all invokeMethod calls with signal.emit()
- Thread callbacks now emit signals instead of calling invokeMethod
- UI updates happen in main Qt thread via signal/slot mechanism

This is the correct PyQt6 way to do cross-thread communication.
All UI updates are now thread-safe and won't cause TypeErrors.

plugins/skill_scanner/plugin.py

@@ -150,8 +150,12 @@ class SkillScannerPlugin(BasePlugin):
     description = "Uses core OCR and Log services"
     hotkey = "ctrl+shift+s"
     
-    # Signal for thread-safe hotkey scanning
+    # Signals for thread-safe UI updates
     hotkey_triggered = pyqtSignal()
+    update_status_signal = pyqtSignal(str, bool, bool)  # message, success, error
+    update_session_table_signal = pyqtSignal(object)  # skills dict
+    update_counters_signal = pyqtSignal()
+    enable_scan_button_signal = pyqtSignal(bool)
     
     def initialize(self):
         """Setup skill scanner."""
@@ -167,8 +171,12 @@ class SkillScannerPlugin(BasePlugin):
         self.current_scan_session = {}  # Skills collected in current multi-page scan
         self.pages_scanned = 0
         
-        # Connect hotkey signal
+        # Connect signals
         self.hotkey_triggered.connect(self._scan_page_for_multi)
+        self.update_status_signal.connect(self._update_multi_page_status_slot)
+        self.update_session_table_signal.connect(self._update_session_table)
+        self.update_counters_signal.connect(self._update_counters_slot)
+        self.enable_scan_button_signal.connect(self.scan_page_btn.setEnabled)
         
         # Subscribe to skill gain events from core Log service
         try:
@@ -514,7 +522,7 @@ class SkillScannerPlugin(BasePlugin):
                 
                 ocr_service = get_ocr_service()
                 if not ocr_service.is_available():
-                    self._update_multi_page_status("Error: OCR not available", error=True)
+                    self.update_status_signal.emit("Error: OCR not available", False, True)
                     return
                 
                 # Capture and OCR
@@ -530,33 +538,22 @@ class SkillScannerPlugin(BasePlugin):
                 
                 self.pages_scanned += 1
                 
-                # Update UI
+                # Update UI via signals (thread-safe)
-                from PyQt6.QtCore import QMetaObject, Qt, Q_ARG
+                self.update_session_table_signal.emit(self.current_scan_session)
-                QMetaObject.invokeMethod(
-                    self, "_update_session_table",
-                    Qt.ConnectionType.QueuedConnection,
-                    Q_ARG(object, self.current_scan_session)
-                )
                 
                 # Show success with checkmark and beep
-                self._update_multi_page_status(
+                self.update_status_signal.emit(
                     f"✅ Page {self.pages_scanned} scanned! {len(skills)} skills found. Click Next Page in game →",
-                    success=True
+                    True, False
                 )
                 
                 # Play beep sound
                 self._play_beep()
                 
             except Exception as e:
-                self._update_multi_page_status(f"Error: {str(e)}", error=True)
+                self.update_status_signal.emit(f"Error: {str(e)}", False, True)
             finally:
-                from PyQt6.QtCore import QMetaObject, Qt, Q_ARG
+                self.enable_scan_button_signal.emit(True)
-                QMetaObject.invokeMethod(
-                    self.scan_page_btn,
-                    "setEnabled",
-                    Qt.ConnectionType.QueuedConnection,
-                    Q_ARG(bool, True)
-                )
         
         thread = Thread(target=do_scan)
         thread.daemon = True
@@ -609,38 +606,18 @@ class SkillScannerPlugin(BasePlugin):
         
         return skills
     
-    def _update_multi_page_status(self, message, success=False, error=False):
+    def _update_multi_page_status_slot(self, message, success=False, error=False):
-        """Update multi-page status label."""
+        """Slot for updating multi-page status (called via signal)."""
-        from PyQt6.QtCore import QMetaObject, Qt, Q_ARG
-        
         color = "#4ecdc4" if success else "#ff4757" if error else "#ff8c42"
         
-        QMetaObject.invokeMethod(
+        self.multi_page_status.setText(message)
-            self.multi_page_status,
+        self.multi_page_status.setStyleSheet(f"color: {color}; font-size: 14px;")
-            "setText",
+        self._update_counters_slot()
-            Qt.ConnectionType.QueuedConnection,
-            Q_ARG(str, message)
-        )
-        QMetaObject.invokeMethod(
-            self.multi_page_status,
-            "setStyleSheet",
-            Qt.ConnectionType.QueuedConnection,
-            Q_ARG(str, f"color: {color}; font-size: 14px;")
-        )
     
-        # Update counters
+    def _update_counters_slot(self):
-        QMetaObject.invokeMethod(
+        """Slot for updating counters (called via signal)."""
-            self.pages_scanned_label,
+        self.pages_scanned_label.setText(f"Pages: {self.pages_scanned}")
-            "setText",
+        self.total_skills_label.setText(f"Skills: {len(self.current_scan_session)}")
-            Qt.ConnectionType.QueuedConnection,
-            Q_ARG(str, f"Pages: {self.pages_scanned}")
-        )
-        QMetaObject.invokeMethod(
-            self.total_skills_label,
-            "setText",
-            Qt.ConnectionType.QueuedConnection,
-            Q_ARG(str, f"Skills: {len(self.current_scan_session)}")
-        )
     
     def _play_beep(self):
         """Play a beep sound to notify user."""
@@ -715,7 +692,7 @@ class SkillScannerPlugin(BasePlugin):
             self._start_auto_scan_with_hotkey()
         elif mode == 1:  # Hotkey only
             self._register_hotkey()
-            self._update_multi_page_status("Hotkey F12 ready! Navigate to first page and press F12", success=True)
+            self.update_status_signal.emit("Hotkey F12 ready! Navigate to first page and press F12", True, False)
         else:  # Manual click
             self._scan_page_for_multi()
     
@@ -729,7 +706,7 @@ class SkillScannerPlugin(BasePlugin):
         self._register_hotkey()
         
         # Start monitoring
-        self._update_multi_page_status("🤖 Auto-detect started! Navigate to page 1...", success=True)
+        self.update_status_signal.emit("🤖 Auto-detect started! Navigate to page 1...", True, False)
         
         # Start auto-detection timer
         self.auto_scan_timer = QTimer()
@@ -797,7 +774,7 @@ class SkillScannerPlugin(BasePlugin):
                 
                 # If page changed, trigger scan
                 if self.last_page_number is not None and current_page != self.last_page_number:
-                    self._update_multi_page_status(f"📄 Page change detected: {current_page}/{total_pages}", success=True)
+                    self.update_status_signal.emit(f"📄 Page change detected: {current_page}/{total_pages}", True, False)
                     self._scan_page_for_multi()
                 
                 self.last_page_number = current_page
@@ -820,9 +797,9 @@ class SkillScannerPlugin(BasePlugin):
         self.auto_scan_active = False
         
         # Keep hotkey registered
-        self._update_multi_page_status(
+        self.update_status_signal.emit(
             "⚠️ Auto-detect unreliable. Use F12 hotkey to scan each page manually!",
-            error=True
+            False, True
         )
         
         # Play alert sound