feat: 播放页按来源列表切换，新增作者/搜索/hashtag 侧栏

- 播放上下文：作品链接带上来源（搜索、标签、作者、hashtag），上一条/下一条
  在该列表内移动；当前作品不在列表中时退回全部作品的发布时间顺序
- 顶部提示标签显示当前列表与位置，点击打开侧栏列表，✕ 退出
- 侧栏改为「评论 | TA的作品 | 搜索结果/#hashtag」标签页，作品封面网格可就地切换
- 作者模式：打开「TA的作品」进入，关闭侧栏不退出，点提示 ✕ 后回到原来的列表
- 从搜索结果进入或点 hashtag 时自动打开对应列表
- 描述中的 hashtag 可点击，按完整 hashtag 精确匹配（#丰川祥子 不含 #丰川祥子cos）
- 新增 /api/playlist；搜索 SQL 抽到 lib/search-query.ts 与播放页共用，保证顺序一致
- 移动端：底部抽屉、点作品后收起，媒体区支持上下滑切换

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/aweme/[awemeId]/page.tsx

@@ -1,6 +1,8 @@
 import type { Metadata } from "next";
 import BackButton from "@/app/components/BackButton";
 import { getFileUrl } from "@/lib/minio";
+import { parsePlaybackContext } from "@/lib/playback-context";
+import { resolvePlayback } from "@/lib/playback-context.server";
 import { prisma } from "@/lib/prisma";
 import AwemeDetailClient from "./Client";
 import type { AwemeData, VideoTranscript } from "./types";
@@ -45,8 +47,10 @@ export async function generateMetadata({
 
 export default async function AwemeDetail({
   params,
+  searchParams,
 }: {
   params: Promise<{ awemeId: string }>;
+  searchParams: Promise<Record<string, string | string[] | undefined>>;
 }) {
   const id = (await params).awemeId;
 
@@ -71,12 +75,10 @@ export default async function AwemeDetail({
   });
 
   let data: AwemeData;
-  let currentCreatedAt: Date;
   let transcript: VideoTranscript | null = null;
 
   if (video) {
     transcript = video.transcript ?? null;
-    currentCreatedAt = video.created_at;
     data = {
       type: "video",
       aweme_id: video.aweme_id,
@@ -100,7 +102,6 @@ export default async function AwemeDetail({
     };
   } else if (post) {
     const coverImage = post.images[0];
-    currentCreatedAt = post.created_at;
     data = {
       type: "image",
       aweme_id: post.aweme_id,
@@ -129,65 +130,16 @@ export default async function AwemeDetail({
     return <main className="p-8">找不到该作品</main>;
   }
 
-  // Compute prev/next neighbors by created_at across videos and image posts
-  const [newerVideo, newerPost, olderVideo, olderPost] = await Promise.all([
-    prisma.video.findFirst({
-      where: { created_at: { gt: currentCreatedAt } },
-      orderBy: { created_at: "asc" },
-      select: { aweme_id: true, created_at: true },
-    }),
-    prisma.imagePost.findFirst({
-      where: { created_at: { gt: currentCreatedAt } },
-      orderBy: { created_at: "asc" },
-      select: { aweme_id: true, created_at: true },
-    }),
-    prisma.video.findFirst({
-      where: { created_at: { lt: currentCreatedAt } },
-      orderBy: { created_at: "desc" },
-      select: { aweme_id: true, created_at: true },
-    }),
-    prisma.imagePost.findFirst({
-      where: { created_at: { lt: currentCreatedAt } },
-      orderBy: { created_at: "desc" },
-      select: { aweme_id: true, created_at: true },
-    }),
+  const authorId = video?.authorId ?? post?.authorId ?? null;
+  const [playback, authorWorksCount] = await Promise.all([
+    resolvePlayback(id, parsePlaybackContext(await searchParams)),
+    authorId
+      ? Promise.all([
+          prisma.video.count({ where: { authorId } }),
+          prisma.imagePost.count({ where: { authorId } }),
+        ]).then(([videos, posts]) => videos + posts)
+      : 0,
   ]);
-  const pickPrev = (() => {
-    const cands: { aweme_id: string; created_at: Date }[] = [];
-    if (newerVideo)
-      cands.push({
-        aweme_id: newerVideo.aweme_id,
-        created_at: newerVideo.created_at,
-      });
-    if (newerPost)
-      cands.push({
-        aweme_id: newerPost.aweme_id,
-        created_at: newerPost.created_at,
-      });
-    if (cands.length === 0) return null;
-    cands.sort((a, b) => +a.created_at - +b.created_at);
-    return { aweme_id: cands[0].aweme_id };
-  })();
-  const pickNext = (() => {
-    const cands: { aweme_id: string; created_at: Date }[] = [];
-    if (olderVideo)
-      cands.push({
-        aweme_id: olderVideo.aweme_id,
-        created_at: olderVideo.created_at,
-      });
-    if (olderPost)
-      cands.push({
-        aweme_id: olderPost.aweme_id,
-        created_at: olderPost.created_at,
-      });
-    if (cands.length === 0) return null;
-    cands.sort((a, b) => +b.created_at - +a.created_at);
-    return { aweme_id: cands[0].aweme_id };
-  })();
-  const neighbors: {
-    prev: { aweme_id: string } | null;
-    next: { aweme_id: string } | null;
-  } = { prev: pickPrev, next: pickNext };
 
   return (
     <main className="min-h-screen w-full">
@@ -200,7 +152,10 @@ export default async function AwemeDetail({
       </div>
       <AwemeDetailClient
         data={data}
-        neighbors={neighbors}
+        neighbors={playback.neighbors}
+        playbackContext={playback.context}
+        contextQuery={playback.contextQuery}
+        authorWorksCount={authorWorksCount}
         transcript={transcript}
       />
     </main>