Added tag UI placeholder for future search and filtering

.vs/AppFlowy/v17/DocumentLayout.json

@@ -0,0 +1,12 @@
+{
+  "Version": 1,
+  "WorkspaceRootPath": "C:\\Users\\Chithra\\AppFlowy\\",
+  "Documents": [],
+  "DocumentGroupContainers": [
+    {
+      "Orientation": 0,
+      "VerticalTabListWidth": 256,
+      "DocumentGroups": []
+    }
+  ]
+}

.vs/VSWorkspaceState.json

@@ -0,0 +1,8 @@
+{
+  "ExpandedNodes": [
+    "",
+    "\\frontend"
+  ],
+  "SelectedNode": "\\frontend",
+  "PreviewInSolutionExplorer": false
+}

frontend/appflowy_flutter/lib/workspace/application/tag/tag.dart

@@ -0,0 +1,11 @@
+class Tag {
+  final String id;
+  final String name;
+  final int color;
+
+  const Tag({
+    required this.id,
+    required this.name,
+    required this.color,
+  });
+}

frontend/appflowy_flutter/lib/workspace/application/tag/tag_filter.dart

@@ -0,0 +1,13 @@
+import 'tag.dart';
+
+class TagFilter {
+  static bool match({
+    required List<Tag> tags,
+    required String query,
+  }) {
+    if (query.isEmpty) return true;
+
+    final lower = query.toLowerCase();
+    return tags.any((tag) => tag.name.toLowerCase().contains(lower));
+  }
+}

frontend/appflowy_flutter/lib/workspace/presentation/home/home_stack.dart

@@ -29,9 +29,11 @@ import 'package:provider/provider.dart';
 import 'package:time/time.dart';
 import 'package:universal_platform/universal_platform.dart';
 import 'package:window_manager/window_manager.dart';
-
 import 'home_layout.dart';
 
+import '../widgets/tags/tag_search_bar.dart';
+
+
 typedef NavigationCallback = void Function(String id);
 
 abstract class HomeStackDelegate {
@@ -80,6 +82,17 @@ class _HomeStackState extends State<HomeStack> with WindowListener {
                 },
               ),
             ),
+
+            //tag feature 
+            Padding(
+              padding: const EdgeInsets.symmetric(horizontal: 16),
+              child: TagSearchBar(
+                onChanged: (query) {
+                  // TEMP: just prints text
+                  debugPrint('Search query: $query');
+                },
+              ),
+            ),
             Expanded(
               child: IndexedStack(
                 index: selectedIndex,

frontend/appflowy_flutter/lib/workspace/presentation/widgets/tags/tag_editor.dart

@@ -0,0 +1,66 @@
+import 'package:flutter/material.dart';
+import '../../../application/tag/tag.dart';
+
+class TagEditor extends StatefulWidget {
+  final List<Tag> tags;
+  final ValueChanged<List<Tag>> onChanged;
+
+  const TagEditor({
+    super.key,
+    required this.tags,
+    required this.onChanged,
+  });
+
+  @override
+  State<TagEditor> createState() => _TagEditorState();
+}
+
+class _TagEditorState extends State<TagEditor> {
+  final controller = TextEditingController();
+
+  void _addTag(String value) {
+    if (value.trim().isEmpty) return;
+
+    widget.onChanged([
+      ...widget.tags,
+      Tag(
+        id: DateTime.now().millisecondsSinceEpoch.toString(),
+        name: value.trim(),
+        color: Colors.blue.value,
+      ),
+    ]);
+
+    controller.clear();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: [
+        Wrap(
+          spacing: 6,
+          children: widget.tags.map((tag) {
+            return Chip(
+              label: Text(tag.name),
+              onDeleted: () {
+                widget.onChanged(
+                  widget.tags.where((t) => t.id != tag.id).toList(),
+                );
+              },
+            );
+          }).toList(),
+        ),
+        const SizedBox(height: 6),
+        TextField(
+          controller: controller,
+          onSubmitted: _addTag,
+          decoration: const InputDecoration(
+            hintText: 'Add tag',
+            isDense: true,
+          ),
+        ),
+      ],
+    );
+  }
+}

frontend/appflowy_flutter/lib/workspace/presentation/widgets/tags/tag_search_bar.dart

@@ -0,0 +1,25 @@
+import 'package:flutter/material.dart';
+
+class TagSearchBar extends StatelessWidget {
+  final ValueChanged<String> onChanged;
+
+  const TagSearchBar({
+    super.key,
+    required this.onChanged,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return Padding(
+      padding: const EdgeInsets.all(8),
+      child: TextField(
+        decoration: const InputDecoration(
+          hintText: 'Search by tag...',
+          prefixIcon: Icon(Icons.search),
+          border: OutlineInputBorder(),
+        ),
+        onChanged: onChanged,
+      ),
+    );
+  }
+}