fix(app): 修复 4 个 Flutter 交互问题

1. 首页数据不刷新 — JournalRepository 添加 onJournalChanged
   Stream 变更通知，HomeBloc 订阅后自动刷新
2. 画笔再次点击不弹出面板 — 添加 ToolReactivated 事件，
   工具栏检测已激活工具时发出重新激活信号
3. 钢笔铅笔效果一样 — 调整 perfect_freehand 参数
   (pen: size 10/smooth 0.65, pencil: size 3/smooth 0.35)
4. 橡皮擦不生效 — ActiveStrokePainter 橡皮擦模式绘制
   半透明灰色反馈，笔画完成后 setState 触发 Layer 1 重绘
5. 贴纸文字无法缩放 — DraggableElement 用 Scale 手势
   替换 Pan 手势，支持双指缩放和旋转

app/lib/features/editor/widgets/active_stroke_painter.dart

@@ -53,6 +53,16 @@ class ActiveStrokePainter extends CustomPainter {
 
     final path = buildStrokePath(outlinePoints);
 
+    // 橡皮擦实时反馈：绘制半透明灰色，让用户看到擦除范围
+    // 实际擦除在笔画完成后的合成图中通过 BlendMode.dstOut 执行
+    if (brushType == BrushType.eraser) {
+      canvas.drawPath(path, Paint()
+        ..color = const Color(0x40808080) // 25% 灰色
+        ..style = PaintingStyle.fill
+        ..isAntiAlias = true);
+      return;
+    }
+
     // 构造临时 Stroke 用于获取 Paint
     final stroke = Stroke(
       id: '__active__',

app/lib/features/editor/widgets/draggable_element.dart

@@ -19,6 +19,8 @@ class DraggableElement extends StatefulWidget {
   final bool isSelected;
   final ValueChanged<String> onTap;
   final void Function(String id, double x, double y) onMoved;
+  final void Function(String id, double w, double h)? onResized;
+  final void Function(String id, double rotation)? onRotated;
   final ValueChanged<String> onDeleted;
 
   const DraggableElement({
@@ -27,6 +29,8 @@ class DraggableElement extends StatefulWidget {
     this.isSelected = false,
     required this.onTap,
     required this.onMoved,
+    this.onResized,
+    this.onRotated,
     required this.onDeleted,
   });
 
@@ -41,6 +45,11 @@ class _DraggableElementState extends State<DraggableElement> {
   late double _height;
   late double _rotation;
 
+  // Scale 手势状态
+  double _baseWidth = 0;
+  double _baseHeight = 0;
+  double _baseRotation = 0;
+
   @override
   void initState() {
     super.initState();
@@ -76,15 +85,35 @@ class _DraggableElementState extends State<DraggableElement> {
       child: Transform.rotate(
         angle: _rotation,
         child: GestureDetector(
-          // 拖拽移动
-          onPanUpdate: (details) {
+          // 缩放开始 — 记录基准值
+          onScaleStart: (details) {
+            _baseWidth = _width;
+            _baseHeight = _height;
+            _baseRotation = _rotation;
+          },
+          // 缩放更新 — 支持单指拖拽 + 双指缩放/旋转
+          onScaleUpdate: (details) {
             setState(() {
-              _x += details.delta.dx;
-              _y += details.delta.dy;
+              // 拖拽（单指和双指都支持）
+              _x += details.focalPointDelta.dx;
+              _y += details.focalPointDelta.dy;
+
+              // 双指缩放 + 旋转
+              if (details.pointerCount >= 2) {
+                final newW = (_baseWidth * details.scale).clamp(40.0, 400.0);
+                final newH = (_baseHeight * details.scale).clamp(40.0, 400.0);
+                _width = newW;
+                _height = newH;
+                _rotation = _baseRotation + details.rotation;
+              }
             });
             widget.onMoved(widget.element.id, _x, _y);
+            if (details.pointerCount >= 2) {
+              widget.onResized?.call(widget.element.id, _width, _height);
+              widget.onRotated?.call(widget.element.id, _rotation);
+            }
           },
-          onPanEnd: (_) {
+          onScaleEnd: (_) {
             // 确保最终位置已通知
             widget.onMoved(widget.element.id, _x, _y);
           },

app/lib/features/editor/widgets/editor_toolbar.dart

@@ -68,7 +68,7 @@ class EditorToolbar extends StatelessWidget {
     final colorScheme = Theme.of(context).colorScheme;
 
     return GestureDetector(
-      onTap: () => onEvent(ToolChanged(tool)),
+      onTap: () => onEvent(isActive ? ToolReactivated(tool) : ToolChanged(tool)),
       behavior: HitTestBehavior.opaque,
       child: Container(
         constraints: const BoxConstraints(minWidth: 36, minHeight: 36),

app/lib/features/editor/widgets/handwriting_canvas.dart

@@ -235,7 +235,10 @@ class _HandwritingCanvasState extends State<HandwritingCanvas> {
     widget.onStrokeCompleted?.call(stroke);
 
     // 光栅化新笔画到缓存（异步，不阻塞 UI）
-    _cache.addStroke(stroke);
+    // 完成后 setState 确保 Layer 1 (CachedStrokesPainter) 用新合成图重绘
+    _cache.addStroke(stroke).then((_) {
+      if (mounted) setState(() {});
+    });
   }
 
   /// 指针取消（如来电打断）：丢弃当前笔画。

app/lib/features/editor/widgets/stroke_renderer.dart

@@ -39,19 +39,21 @@ class _BrushConfig {
 
 /// 各画笔的渲染参数。
 const Map<BrushType, _BrushConfig> _brushConfigs = {
-  /// 钢笔：中等粗细，强压感变化，模拟毛笔效果
+  /// 钢笔：粗壮平滑，模拟签字笔效果
   BrushType.pen: _BrushConfig(
-    size: 8,
-    thinning: 0.7,
-    smoothing: 0.5,
+    size: 10,
+    thinning: 0.65,
+    smoothing: 0.65,
+    streamline: 0.6,
     simulatePressure: true,
   ),
 
-  /// 铅笔：细线，轻微压感，高平滑度产生自然线条
+  /// 铅笔：纤细有质感，保留书写抖动
   BrushType.pencil: _BrushConfig(
-    size: 4,
-    thinning: 0.3,
-    smoothing: 0.7,
+    size: 3,
+    thinning: 0.4,
+    smoothing: 0.35,
+    streamline: 0.3,
     simulatePressure: true,
   ),