fix(player): 使用根Overlay承载飘心

lib/pages/player/widgets/player_double_tap_hearts.dart

@@ -123,47 +123,43 @@ class _PlayerDoubleTapHeartBurstState extends State<PlayerDoubleTapHeartBurst>
   @override
   Widget build(BuildContext context) {
     return IgnorePointer(
-      child: SizedBox.shrink(
-        child: AnimatedBuilder(
-          animation: _controller,
-          builder: (context, _) {
-            final elapsed =
-                _controller.value * _controller.duration!.inMilliseconds;
-            return Stack(
-              fit: StackFit.expand,
-              clipBehavior: Clip.none,
-              children: [
-                for (var index = 0; index < _hearts.length; index++)
-                  _heart(_hearts[index], elapsed, index),
-                if (kDebugMode)
-                  Positioned(
-                    left: widget.origin.dx + 8,
-                    top: widget.origin.dy,
-                    child: IgnorePointer(
-                      child: Text(
-                        '${elapsed.round()}ms',
-                        key: const Key('heart-burst-elapsed-debug'),
-                        style: const TextStyle(
-                          color: Colors.white60,
-                          fontSize: 11,
-                        ),
+      child: AnimatedBuilder(
+        animation: _controller,
+        builder: (context, _) {
+          final elapsed =
+              _controller.value * _controller.duration!.inMilliseconds;
+          return Stack(
+            fit: StackFit.expand,
+            clipBehavior: Clip.none,
+            children: [
+              for (var index = 0; index < _hearts.length; index++)
+                _heart(_hearts[index], elapsed, index),
+              if (kDebugMode)
+                Positioned(
+                  left: widget.origin.dx + 8,
+                  top: widget.origin.dy + 10,
+                  child: IgnorePointer(
+                    child: Text(
+                      '${elapsed.round()}ms',
+                      key: const Key('heart-burst-elapsed-debug'),
+                      style: const TextStyle(
+                        color: Colors.white60,
+                        fontSize: 11,
                       ),
                     ),
                   ),
-              ],
-            );
-          },
-        ),
+                ),
+            ],
+          );
+        },
       ),
     );
   }
 
   Widget _heart(_HeartParticle heart, double elapsed, int index) {
-    final progress = ((elapsed - heart.delay) / _heartDurationMs).clamp(
-      0.0,
-      1.0,
-    );
-    if (progress <= 0) return const SizedBox.shrink();
+    final rawProgress = (elapsed - heart.delay) / _heartDurationMs;
+    if (rawProgress < 0) return const SizedBox.shrink();
+    final progress = rawProgress.clamp(0.0, 1.0);
     final move = Curves.easeOutCubic.transform(progress);
     final scale = progress < _heartPopPortion
         ? _heartStartScale +

test/player/player_double_tap_hearts_test.dart

@@ -57,6 +57,48 @@ void main() {
     expect(_opacity(tester, 0), lessThan(0.5));
   });
 
+  testWidgets('heart position is anchored to the overlay origin', (
+    tester,
+  ) async {
+    const origin = Offset(300, 546);
+    await tester.pumpWidget(
+      const MaterialApp(
+        home: Scaffold(
+          body: Stack(
+            fit: StackFit.expand,
+            children: [
+              Positioned.fill(
+                child: PlayerDoubleTapHeartBurst(
+                  burstId: 4,
+                  origin: origin,
+                  onCompleted: _noop,
+                ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+
+    final firstHeart = find.byKey(const Key('double-tap-heart-0'));
+    expect(
+      (tester.getCenter(firstHeart) - origin).distance,
+      lessThanOrEqualTo(1),
+    );
+    final debugTopLeft = tester.getTopLeft(
+      find.byKey(const Key('heart-burst-elapsed-debug')),
+    );
+    expect(
+      (debugTopLeft - const Offset(308, 556)).distance,
+      lessThanOrEqualTo(1),
+    );
+
+    await tester.pump(const Duration(milliseconds: 750));
+    final midpoint = tester.getCenter(firstHeart);
+    expect(midpoint.dy, lessThan(origin.dy));
+    expect((midpoint.dx - origin.dx).abs(), lessThanOrEqualTo(1));
+  });
+
   testWidgets('develop heart burst completes after about 1590ms', (
     tester,
   ) async {