fix：第一轮跑

lib/features/ads/presentation/ad_media.dart

@@ -0,0 +1,122 @@
+import 'dart:async';
+import 'dart:io' show File;
+
+import 'package:flutter/foundation.dart' show kIsWeb;
+import 'package:flutter/material.dart';
+import 'package:video_player/video_player.dart';
+
+import '../data/ads_api_client.dart';
+
+/// 统一渲染广告图片/GIF/视频；开屏可优先使用已缓存的本地素材。
+class AdMedia extends StatefulWidget {
+  const AdMedia({
+    super.key,
+    required this.ad,
+    this.assetPath,
+    this.fit = BoxFit.cover,
+  });
+  final AdCreative ad;
+  final String? assetPath;
+  final BoxFit fit;
+  @override
+  State<AdMedia> createState() => _AdMediaState();
+}
+
+class _AdMediaState extends State<AdMedia> {
+  VideoPlayerController? player;
+  bool ready = false, failed = false;
+  @override
+  void initState() {
+    super.initState();
+    _load();
+  }
+
+  @override
+  void didUpdateWidget(covariant AdMedia old) {
+    super.didUpdateWidget(old);
+    if (old.ad.adId != widget.ad.adId || old.assetPath != widget.assetPath) {
+      unawaited(player?.dispose() ?? Future.value());
+      player = null;
+      ready = false;
+      failed = false;
+      _load();
+    }
+  }
+
+  void _load() {
+    if (widget.ad.mediaType != AdMediaType.video) return;
+    final uri = widget.ad.mediaUri;
+    if (uri == null) return;
+    final path = widget.assetPath;
+    final controller = !kIsWeb && path != null && path.isNotEmpty
+        ? VideoPlayerController.file(File(path))
+        : VideoPlayerController.networkUrl(uri);
+    player = controller;
+    unawaited(
+      controller
+          .initialize()
+          .then((_) async {
+            await controller.setLooping(true);
+            await controller.setVolume(0);
+            await controller.play();
+            if (mounted) setState(() => ready = true);
+          })
+          .catchError((_) {
+            if (mounted) setState(() => failed = true);
+          }),
+    );
+  }
+
+  @override
+  void dispose() {
+    player?.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    if (widget.ad.mediaType != AdMediaType.video) {
+      final path = widget.assetPath;
+      if (!kIsWeb && path != null && path.isNotEmpty) {
+        return Image.file(
+          File(path),
+          fit: widget.fit,
+          width: double.infinity,
+          height: double.infinity,
+          errorBuilder: (_, _, _) => _error(),
+        );
+      }
+      return Image.network(
+        widget.ad.imageUrl,
+        fit: widget.fit,
+        width: double.infinity,
+        height: double.infinity,
+        errorBuilder: (_, _, _) => _error(),
+      );
+    }
+    final c = player;
+    if (failed) return _error();
+    if (c == null || !ready) {
+      return const ColoredBox(
+        color: Color(0xFF161616),
+        child: Center(child: CircularProgressIndicator()),
+      );
+    }
+    return FittedBox(
+      fit: widget.fit,
+      clipBehavior: Clip.hardEdge,
+      child: SizedBox(
+        width: c.value.size.width,
+        height: c.value.size.height,
+        child: VideoPlayer(c),
+      ),
+    );
+  }
+
+  Widget _error() => const ColoredBox(
+    color: Color(0xFF161616),
+    child: Center(
+      child: Icon(Icons.broken_image_outlined, color: Colors.white54),
+    ),
+  );
+}