Fix: Invisible overlay blocking mouse clicks

Problem:
The overlay window, even when fully transparent or visually hidden (opacity 0), was still intercepting mouse events. This created a 'dead zone' on the screen where users could not click through to applications behind the overlay. This occurred because the low-level window hook was answering 'HTCAPTION' to hit tests regardless of the UI state.

Solution:
1. Modified 'WindowHook' to accept an 'enabled' state.
2. When disabled, 'WM_NCHITTEST' now returns 'HTTRANSPARENT', allowing the OS to pass the click to the window underneath.
3. Updated 'main.py' to toggle this hook state dynamically:
   - ENABLED when Recording or Processing (UI is visible/active).
   - DISABLED when Idling (UI is hidden/transparent).

Result:
The overlay is now completely non-intrusive when not in use.

main.py

@@ -222,12 +222,23 @@ class WhisperApp(QObject):
             self.settings_root.setVisible(False)
         
         # Install Low-Level Window Hook for Transparent Hit Test
-        # We must keep a reference to 'self.hook' so it isn't GC'd
-        # scale = self.overlay_root.devicePixelRatio()
-        # self.hook = WindowHook(int(self.overlay_root.winId()), 500, 300, scale)
-        # self.hook.install()
-        
-        # NOTE: HitTest hook will be installed here later
+        try:
+            from src.utils.window_hook import WindowHook
+            hwnd = self.overlay_root.winId()
+            # Initial scale from config
+            scale = float(self.config.get("ui_scale"))
+            
+            # Current Overlay Dimensions
+            win_w = int(460 * scale)
+            win_h = int(180 * scale)
+            
+            self.window_hook = WindowHook(hwnd, win_w, win_h, initial_scale=scale)
+            self.window_hook.install()
+            
+            # Initial state: Disabled because we start inactive
+            self.window_hook.set_enabled(False)
+        except Exception as e:
+            logging.error(f"Failed to install WindowHook: {e}")
 
     def center_overlay(self):
         """Calculates and sets the Overlay position above the taskbar."""
@@ -531,6 +542,25 @@ class WhisperApp(QObject):
         self.bridge.update_status("Error")
         logging.error(f"Download Error: {err}")
 
+    @Slot(bool)
+    def on_ui_toggle_request(self, is_recording):
+        """Called when recording state changes."""
+        # Update Window Hook to allow clicking if active
+        is_active = is_recording or self.bridge.isProcessing
+        if hasattr(self, 'window_hook'):
+            self.window_hook.set_enabled(is_active)
+            
+    @Slot(bool)
+    def on_processing_changed(self, is_processing):
+        is_active = self.bridge.isRecording or is_processing
+        if hasattr(self, 'window_hook'):
+            self.window_hook.set_enabled(is_active)
+
 if __name__ == "__main__":
+    import sys
     app = WhisperApp()
-    app.run()
+    
+    # Connect extra signal for processing state
+    app.bridge.isProcessingChanged.connect(app.on_processing_changed)
+    
+    sys.exit(app.run())