fix(player): 修复返回首页黑屏并恢复预热

lib/core/data/services/playback_neighbors.dart

@@ -69,7 +69,6 @@ Future<void> _placeNeighbor(PlaybackSession session, _PlayerSlot? slot) async {
 
 /// 当前集已经出画后，按手势方向静默准备上一集和下一集。
 void _warmNeighbors(PlaybackSession session, {bool preferredNext = true}) {
-  if (!session.warmNeighborsEnabled) return;
   final request = session._generation;
   final nextTask = _warmOne(session, request, session._nextIndex, next: true);
   final previousTask = _warmOne(

lib/core/data/services/playback_session.dart

@@ -27,7 +27,6 @@ class PlaybackSession extends ChangeNotifier {
     this.activate,
     PlaybackCoordinator? coordinator,
     this.waitForFrame,
-    this.warmNeighborsEnabled = true,
   }) : _coordinator = coordinator ?? PlaybackCoordinator();
 
   final List<Episode> episodes;
@@ -40,7 +39,6 @@ class PlaybackSession extends ChangeNotifier {
   /// Runs only when a slot becomes current (e.g. progress listeners).
   final PlayerPreparation? activate;
   final Future<void> Function()? waitForFrame;
-  final bool warmNeighborsEnabled;
   final PlaybackCoordinator _coordinator;
   final Set<_PlayerSlot> _live = {};
   _PlayerSlot? _active;
@@ -142,8 +140,8 @@ class PlaybackSession extends ChangeNotifier {
   }
 
   void _rememberNeighbors(int? preloadIndex, int? previousIndex) {
-    _nextIndex = warmNeighborsEnabled ? preloadIndex : null;
-    _previousIndex = warmNeighborsEnabled ? previousIndex : null;
+    _nextIndex = preloadIndex;
+    _previousIndex = previousIndex;
   }
 
   Future<void> _enqueue(Future<void> Function() operation) {

lib/core/data/services/playback_session_controls.dart

@@ -6,12 +6,7 @@ part of 'playback_session.dart';
 extension PlaybackSessionControls on PlaybackSession {
   /// 滑动手势开始时按方向优先准备相邻集，不改变当前集播放状态。
   void prewarmNeighbors({required bool forward}) {
-    if (!warmNeighborsEnabled ||
-        !_visible ||
-        _overlayOpen ||
-        _active?.prepared != true) {
-      return;
-    }
+    if (!_visible || _overlayOpen || _active?.prepared != true) return;
     _warmNeighbors(this, preferredNext: forward);
   }
 
@@ -62,6 +57,7 @@ extension PlaybackSessionControls on PlaybackSession {
         slot.activated = true;
       }
       await _applyPlayback(slot);
+      if (_visible && !_overlayOpen && !_loading) _warmNeighbors(this);
       if (kDebugMode) {
         debugPrint(
           '[feed-handoff] phase=resumed activated=${slot.activated} '

lib/core/data/services/video_player_port.dart

@@ -2,6 +2,7 @@
 
 import 'dart:io';
 
+import 'package:flutter/foundation.dart';
 import 'package:video_player/video_player.dart';
 
 import '../../config/app_config.dart';
@@ -68,6 +69,13 @@ class VideoPlayerPort implements PlayerPort {
   Future<void> dispose() async {
     if (_disposed) return;
     _disposed = true;
+    if (kDebugMode) {
+      debugPrint(
+        '[player-controller] phase=dispose '
+        'controller=${identityHashCode(controller)} '
+        'source=${controller.dataSource}\n${StackTrace.current}',
+      );
+    }
     try {
       await _initialization;
     } catch (_) {