feat(ks): 支持分享短链 /f/<token> 形式的视频输入

快手分享短链 https://www.kuaishou.com/f/X9Idt15MQb9L2cv 路径里是 share_token
而不是视频 ID，它只做 302 跳转，真实地址在 Location 里。原先的解析器只认
/short-video/<id> 和纯 ID，遇到短链会抛 ValueError 被 continue 掉——只有一行
ERROR 日志，看起来像"爬了但没数据"。

- help.py: 新增 /f/<token> 分支，返回 url_type="short"（token 不是视频 ID，
  必须跟随重定向），并补上第三种形式的文档
- client.py: 新增 resolve_short_url，GET 时 follow_redirects=False，读
  301/302/303/307/308 的 Location
- core.py: url_type == "short" 时先解析短链再解析一次，失败则跳过该条
- 新增 tests/test_kuaishou_url_parse.py（6 条，不发网络请求）

验证：两条真实短链分别解析到 3xyziwesje8e9jg / 3xbbkdxtxqm8sae，详情均成功；
带 query 的标准视频页不会被误判成短链。

media_platform/kuaishou/client.py

@@ -240,6 +240,37 @@ class KuaiShouClient(AbstractApiClient, ProxyRefreshMixin):
         }
         return await self.post("", post_data)
 
+    async def resolve_short_url(self, short_url: str) -> str:
+        """解析快手分享短链（/f/xxx），返回重定向后的真实 URL。
+
+        短链路径里的 share_token 不是视频 ID，只能靠 302 的 Location 拿到
+        /short-video/<id> 形式的真实地址。
+        """
+        async with make_async_client(proxy=self.proxy, follow_redirects=False) as client:
+            try:
+                utils.logger.info(
+                    f"[KuaiShouClient.resolve_short_url] Resolving short URL: {short_url}"
+                )
+                response = await client.get(short_url, timeout=10, headers=self.headers)
+
+                # 短链通常返回 302
+                if response.status_code in (301, 302, 303, 307, 308):
+                    redirect_url = response.headers.get("Location", "")
+                    utils.logger.info(
+                        f"[KuaiShouClient.resolve_short_url] Resolved to: {redirect_url}"
+                    )
+                    return redirect_url
+
+                utils.logger.warning(
+                    f"[KuaiShouClient.resolve_short_url] Unexpected status code: {response.status_code}"
+                )
+                return ""
+            except Exception as e:
+                utils.logger.error(
+                    f"[KuaiShouClient.resolve_short_url] Failed to resolve short URL: {e}"
+                )
+                return ""
+
     async def get_video_info(self, photo_id: str) -> Dict:
         """
         Kuaishou web video detail api

media_platform/kuaishou/core.py

@@ -204,6 +204,24 @@ class KuaishouCrawler(AbstractCrawler):
         for video_url in config.KS_SPECIFIED_ID_LIST:
             try:
                 video_info = parse_video_info_from_url(video_url)
+
+                # 分享短链（/f/xxx）要先跟随 302 重定向，才能拿到 /short-video/<id>
+                if video_info.url_type == "short":
+                    utils.logger.info(
+                        f"[KuaishouCrawler.get_specified_videos] Resolving short link: {video_url}"
+                    )
+                    resolved_url = await self.ks_client.resolve_short_url(video_url)
+                    if resolved_url:
+                        video_info = parse_video_info_from_url(resolved_url)
+                        utils.logger.info(
+                            f"[KuaishouCrawler.get_specified_videos] Short link resolved to video ID: {video_info.video_id}"
+                        )
+                    else:
+                        utils.logger.error(
+                            f"[KuaishouCrawler.get_specified_videos] Failed to resolve short link: {video_url}"
+                        )
+                        continue
+
                 video_ids.append(video_info.video_id)
                 utils.logger.info(f"Parsed video ID: {video_info.video_id} from {video_url}")
             except ValueError as e:

media_platform/kuaishou/help.py

@@ -92,6 +92,8 @@ def parse_video_info_from_url(url: str) -> VideoUrlInfo:
     Supports the following formats:
     1. Full video URL: "https://www.kuaishou.com/short-video/3x3zxz4mjrsc8ke?authorId=3x84qugg4ch9zhs&streamSource=search"
     2. Pure video ID: "3x3zxz4mjrsc8ke"
+    3. Share short link: "https://www.kuaishou.com/f/X9Idt15MQb9L2cv"
+       （路径里是 share_token 而非视频 ID，返回 url_type="short"，由调用方跟随重定向）
 
     Args:
         url: Kuaishou video link or video ID
@@ -109,6 +111,14 @@ def parse_video_info_from_url(url: str) -> VideoUrlInfo:
         video_id = match.group(1)
         return VideoUrlInfo(video_id=video_id, url_type="normal")
 
+    # 分享短链：https://www.kuaishou.com/f/X9Idt15MQb9L2cv
+    # 路径里的 share_token 不是视频 ID，必须跟随 302 重定向才能拿到真实地址，
+    # 所以这里只标记类型，交给调用方解析（url_type="short"）
+    share_pattern = r'kuaishou\.com/f/([a-zA-Z0-9_-]+)'
+    match = re.search(share_pattern, url)
+    if match:
+        return VideoUrlInfo(video_id=match.group(1), url_type="short")
+
     raise ValueError(f"Unable to parse video ID from URL: {url}")