style(player): 播放页与首页浮层的控件样式统一

播放页顶部按钮与选集条去掉底色、进度条不再画滑块圆点并压到最底部；
剧名与简介收在互动栏左侧，清屏后只留右下角退出按钮。
首页观看条与进度条共用 20pt 页边距，进度槽底色与播放页一致。

test/player/seek_scrub_visibility_test.dart

@@ -37,11 +37,8 @@ void main() {
     expect(find.byKey(const Key('scrub-overlay')), findsNothing);
     expect(harness.scrubStarts, 1);
     expect(_sliderTheme(tester).trackHeight, 6);
-    expect(
-      (_sliderTheme(tester).thumbShape! as RoundSliderThumbShape)
-          .enabledThumbRadius,
-      8,
-    );
+    // 不画滑块圆点，进度只靠已播段表达。
+    expect(_sliderTheme(tester).thumbShape, SliderComponentShape.noThumb);
 
     await gesture.moveBy(const Offset(72, 0));
     await tester.pump();
@@ -67,11 +64,7 @@ void main() {
     expect(harness.scrubEnds, 1);
     expect(harness.seeks, 1);
     expect(_sliderTheme(tester).trackHeight, 2);
-    expect(
-      (_sliderTheme(tester).thumbShape! as RoundSliderThumbShape)
-          .enabledThumbRadius,
-      6,
-    );
+    expect(_sliderTheme(tester).thumbShape, SliderComponentShape.noThumb);
   });
 
   testWidgets('feed progress tap does not clear overlay content', (
@@ -154,29 +147,27 @@ void main() {
     await tester.pumpAndSettle();
   });
 
-  testWidgets('feed progress thumb stays on the finger when dragged right', (
-    tester,
-  ) async {
-    await _pumpFeedOverlay(tester);
-    final bar = find.byKey(const Key('home-feed-progress'));
-    final gesture = await tester.startGesture(tester.getCenter(bar));
+  testWidgets(
+    'feed progress played segment follows the finger when dragged right',
+    (tester) async {
+      await _pumpFeedOverlay(tester);
+      final bar = find.byKey(const Key('home-feed-progress'));
+      final gesture = await tester.startGesture(tester.getCenter(bar));
 
-    await gesture.moveBy(const Offset(800, 0));
-    await tester.pump();
+      await gesture.moveBy(const Offset(800, 0));
+      await tester.pump();
 
-    final thumbCenter = tester
-        .getRect(find.byKey(const Key('home-feed-progress-thumb')))
-        .center
-        .dx;
-    final playedRight = tester
-        .getRect(find.byKey(const Key('home-feed-progress-played')))
-        .right;
-    expect(thumbCenter, closeTo(tester.getRect(bar).right, 0.5));
-    expect(playedRight, closeTo(thumbCenter, 0.5));
+      expect(
+        tester
+            .getRect(find.byKey(const Key('home-feed-progress-played')))
+            .right,
+        closeTo(tester.getRect(bar).right, 0.5),
+      );
 
-    await gesture.up();
-    await tester.pumpAndSettle();
-  });
+      await gesture.up();
+      await tester.pumpAndSettle();
+    },
+  );
 
   testWidgets('full player drag clears chrome and release restores it', (
     tester,