feat(app): 集成贴纸选择到编辑器 — 底部面板 + 自动放置

app/lib/features/editor/views/editor_page.dart

@@ -24,6 +24,7 @@ import '../widgets/draggable_element.dart';
 import '../widgets/editor_toolbar.dart';
 import '../widgets/text_input_overlay.dart';
 import '../widgets/image_picker_handler.dart';
+import '../widgets/sticker_picker_sheet.dart';
 
 /// 手账编辑器页面
 class EditorPage extends StatelessWidget {
@@ -269,6 +270,46 @@ class _EditorStack extends StatefulWidget {
 }
 
 class _EditorStackState extends State<_EditorStack> {
+  EditorTool? _lastTool;
+
+  @override
+  void didUpdateWidget(covariant _EditorStack oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    final currentTool = widget.state.activeTool;
+
+    // 贴纸工具刚被激活时弹出底部面板（防止重复弹窗）
+    if (currentTool == EditorTool.sticker && _lastTool != EditorTool.sticker) {
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        if (mounted) _showStickerPicker();
+      });
+    }
+    _lastTool = currentTool;
+  }
+
+  /// 显示贴纸选择底部面板
+  void _showStickerPicker() {
+    showModalBottomSheet(
+      context: context,
+      isScrollControlled: true,
+      builder: (_) => StickerPickerSheet(
+        onStickerSelected: (emoji) {
+          final center = Offset(
+            MediaQuery.of(context).size.width / 2 - 24,
+            MediaQuery.of(context).size.height / 3,
+          );
+          context.read<EditorBloc>().add(ElementAdded(
+            JournalElement.createSticker(
+              journalId: widget.journalId ?? '',
+              emoji: emoji,
+              position: center,
+            ),
+          ));
+          context.read<EditorBloc>().add(ToolChanged(EditorTool.select));
+        },
+      ),
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
     final state = widget.state;