feat(notes): Improve note editor change detection and UI refinements

lib/features/notes/views/note_editor_page.dart

@@ -117,11 +117,22 @@ class _NoteEditorPageState extends ConsumerState<NoteEditorPage> {
   }
 
   void _onContentChanged() {
-    if (!_hasChanges && mounted) {
-      setState(() => _hasChanges = true);
+    if (!mounted || _isLoading) return;
+
+    // Check if content actually changed from the saved note
+    final titleChanged = _note != null && _titleController.text != _note!.title;
+    final contentChanged =
+        _note != null && _contentController.text != _note!.markdownContent;
+    final hasRealChanges = titleChanged || contentChanged;
+
+    if (hasRealChanges != _hasChanges) {
+      setState(() => _hasChanges = hasRealChanges);
     }
+
+    if (hasRealChanges) {
       _debounceSave();
     }
+  }
 
   void _debounceSave() {
     _saveDebounce?.cancel();
@@ -378,9 +389,7 @@ class _NoteEditorPageState extends ConsumerState<NoteEditorPage> {
   }
 
   Future<void> _startDictation() async {
-    _voiceService ??= VoiceInputService(
-      api: ref.read(apiServiceProvider),
-    );
+    _voiceService ??= VoiceInputService(api: ref.read(apiServiceProvider));
 
     try {
       final ok = await _voiceService!.initialize();
@@ -474,10 +483,12 @@ class _NoteEditorPageState extends ConsumerState<NoteEditorPage> {
       canPop: !_hasChanges,
       onPopInvokedWithResult: (didPop, result) async {
         if (didPop) return; // Already popped, nothing to do
+        // Capture navigator before async gap
+        final navigator = Navigator.of(context);
         // Save changes before allowing pop
         await _saveNote(showFeedback: false);
         if (!mounted) return;
-        Navigator.of(context).pop();
+        navigator.pop();
       },
       child: ErrorBoundary(
         child: Scaffold(
@@ -572,7 +583,9 @@ class _NoteEditorPageState extends ConsumerState<NoteEditorPage> {
 
           // Generate title button - aligned with other header icons
           AnimatedOpacity(
-            opacity: _titleFocusNode.hasFocus && !_isGeneratingTitle ? 1.0 : 0.0,
+            opacity: _titleFocusNode.hasFocus && !_isGeneratingTitle
+                ? 1.0
+                : 0.0,
             duration: const Duration(milliseconds: 150),
             child: IgnorePointer(
               ignoring: !_titleFocusNode.hasFocus || _isGeneratingTitle,
@@ -909,11 +922,7 @@ class _NoteEditorPageState extends ConsumerState<NoteEditorPage> {
                 ),
               ),
             )
-          : Icon(
-              icon,
-              color: color ?? theme.iconPrimary,
-              size: IconSize.lg,
-            ),
+          : Icon(icon, color: color ?? theme.iconPrimary, size: IconSize.lg),
     );
 
     if (showMenu) {