feat(adapters): RSS and PT site adapters ported from MoviePilot v3 + mocks (W1-3b)

- rss: port of MP RssHelper._parse_impl/get_rss_link semantics with safe
  XML (entities off, DTD/ENTITY rejected, size/item caps), ETag/Last-Modified,
  backoff + Retry-After, circuit breaker with manual reset, passkey redaction,
  overlap-window GUID+digest dedupe
- sites/spider: TS port of MP SiteSpider (indexer schema, search URL builder,
  field DSL, filters, Jinja templates via nunjucks, login-page detection);
  audiences definition hand-written as JSON; raw category id preserved;
  shared per-site token bucket
- sites/mteam: port of MP MTorrentSpider (params, result mapping, promo
  factors, genDlToken flow) without embedding the API key in enclosures;
  business code/message checks
- testkit: mock RSS server, mock NexusPHP site, mock M-Team API
- docs: W1-3b migration mapping appended to porting ledger

Co-Authored-By: Claude Fable 5.1 <[email protected]>

packages/testkit/src/sites/README.md

@@ -0,0 +1,30 @@
+# testkit/sites
+
+mock PT 站点(配合 adapters/sites 的 MoviePilot 迁移实现)。HTML/JSON fixture 为自行编写,**不代表已核对真实站点**,只用于验证适配器的选择器配置与错误分类。
+
+## mock NexusPHP(观众风格)
+
+```ts
+const site = await createMockNexusPhpSite({ pageSize: 50, pageBase: 0, loginMode: "page" | "redirect" });
+site.baseUrl; site.cookie;          // 请求 Cookie 需包含 site.cookie
+site.setLoggedIn(false);            // 全站返回登录页(或 302 login.php)
+site.failNext(1, 429, "7");         // 限流 / 5xx
+site.setBrokenLayout(true);         // 改版模拟
+site.infoHashOf("812345");          // 下载 .torrent 的 infohash
+```
+
+路由:`index.php`、`torrents.php`(search / catN / spstate=2 / page)、`details.php?id=`(不存在返回"没有该ID的种子")、`download.php?id=`(合法 .torrent,或 `magnet` 字段时 302 磁力)、`login.php`。
+默认 fixture `AUDIENCES_FIXTURE_RELEASES`:免费+截止(812345)、综艺 403 + H&R(812346)、50%+2x(812347)、截断标题 + TB(812348)、纪录片 2x + KB(812349)。
+
+## mock M-Team API
+
+```ts
+const api = await createMockMteamApi({ apiKey, torrents, failMode });
+api.setFailMode("banned_key" | "rate_limit" | "http_429" | "non_json" | "no_dl_token" | null);
+api.lastSearchBody; api.issuedTokens; api.infoHashOf("912233");
+```
+
+路由:`POST /api/torrent/search`、`/api/torrent/detail`、`/api/torrent/genDlToken`(id 可走 query 或表单,签发一次性 `/api/rss/dlv2?sign=&t=&tid=`)、`/api/member/profile`;`x-api-key` 错误返回 `{code:"1", message:"key無效"}`。
+默认 fixture `MTEAM_FIXTURE_TORRENTS`:50% 限时(912233)、商城单种免费(912234)、全站促销(912235,动画 405)、2x 免费(912236,纪录 404)、体育 407(912237)。
+
+`buildFakeTorrent({name, length})` 生成结构合法的 .torrent 与其 infohash。