feat: Add border color support to NoteCard and DraggableNote for enhanced visual distinction

lib/screens/home_screen.dart

@@ -313,6 +313,10 @@ class _HomeScreenState extends State<HomeScreen> {
     final int crossAxisCount = math.max((width / 250).floor().round(), 2);
     final List<Note> visibleNotes = _getFilteredNotes();
     final Category? currentCategory = _currentCategory();
+    final Map<String, Color> categoryBorderColors = <String, Color>{
+      for (final Category category in _categories)
+        if (category.colorValue != null) category.id: Color(category.colorValue!),
+    };
 
     final Widget body = _isLoading
         ? const Center(child: CircularProgressIndicator())
@@ -371,6 +375,7 @@ class _HomeScreenState extends State<HomeScreen> {
 
                                       final Widget draggableNote = _DraggableNote(
                                         note: filteredNotes[index],
+                                        borderColor: categoryBorderColors[filteredNotes[index].categoryId],
                                         dataIndex: _notes.indexOf(
                                           filteredNotes[index],
                                         ),
@@ -564,6 +569,7 @@ class _HomeScreenState extends State<HomeScreen> {
 class _DraggableNote extends StatelessWidget {
   const _DraggableNote({
     required this.note,
+    this.borderColor,
     required this.dataIndex,
     required this.cellWidth,
     required this.requiresLongPressToDrag,
@@ -576,6 +582,7 @@ class _DraggableNote extends StatelessWidget {
   });
 
   final Note note;
+  final Color? borderColor;
   final int dataIndex;
   final double cellWidth;
   final bool requiresLongPressToDrag;
@@ -611,6 +618,7 @@ class _DraggableNote extends StatelessWidget {
                 note: note,
                 onTap: () {},
                 isDragging: true,
+                borderColor: borderColor,
               ),
             ),
           ),
@@ -629,7 +637,7 @@ class _DraggableNote extends StatelessWidget {
           decoration: BoxDecoration(
             color: const Color.fromRGBO(24, 25, 26, 1),
             borderRadius: BorderRadius.circular(12),
-            border: Border.all(color: Colors.white24, width: 1),
+            border: Border.all(color: borderColor ?? Colors.white24, width: 1),
           ),
           child: Column(
             crossAxisAlignment: CrossAxisAlignment.start,
@@ -673,6 +681,7 @@ class _DraggableNote extends StatelessWidget {
         note: note,
         onTap: onTap,
         isDragging: isDragging,
+        borderColor: borderColor,
       ),
     );