refactor(chain): chain 与 module 仅经 run_module 契约互联，实现模块内容封闭

- mTorrent 字幕链接解析下沉为 IndexerModule.site_subtitle_links，subtitle 模块自行跳过 API 站点
- TMDB/MusicBrainz 识别缓存管理改为模块方法（tmdb_cache_*/music_cache_*）经 run_module 分发
- WechatClawBot 客户端查找/临时客户端/缓存迁移内聚为 wechatclawbot_* 模块方法，
  chain 移除 WechatClawBot 类与 ModuleManager 内省
- LISTENBRAINZ_* 常量迁至 schemas/types.py，模块与链层再导入保持兼容
- TMDbException 升为 schemas/exception.py 跨层契约，vendored 异常保持类身份一致
- 架构守护测试新增 test_chain_does_not_import_module_internals（共 18 项）
- 文档同步：chain->module 仅允许 run_module 分发，直接导入禁止

app/chain/message.py

@@ -35,8 +35,6 @@ from app.application.messaging.site import site_interaction_manager
 from app.application.messaging.skill import SkillInteractionHandler, skill_interaction_manager
 from app.application.messaging.subscribe import subscribe_interaction_manager
 from app.application.torrent import TorrentHelper
-from app.modules.wechatclawbot.wechatclawbot import WechatClawBot
-from app.runtime.extensions.module_manager import ModuleManager
 from app.runtime.log import logger
 from app.schemas import CommingMessage, DownloadDirectory, FileURI, NotExistMediaInfo, Notification
 from app.schemas.message import ChannelCapabilityManager, ChannelCapability
@@ -1854,30 +1852,8 @@ class MessageChain(ChainBase):
             logger.error(e)
             return None
 
-    @staticmethod
-    def _build_wechatclawbot_temp_client(
-            source: Optional[str] = None,
-            WECHATCLAWBOT_BASE_URL: Optional[str] = None,
-            WECHATCLAWBOT_DEFAULT_TARGET: Optional[str] = None,
-            WECHATCLAWBOT_ADMINS: Optional[str] = None,
-            WECHATCLAWBOT_POLL_TIMEOUT: Optional[int] = None,
-    ):
-        """基于当前表单配置创建一个临时客户端，用于未保存时的扫码状态预览。"""
-        source_name = str(source or "").strip()
-        if not source_name:
-            return None
-        return WechatClawBot(
-            name=source_name,
-            WECHATCLAWBOT_BASE_URL=WECHATCLAWBOT_BASE_URL,
-            WECHATCLAWBOT_DEFAULT_TARGET=WECHATCLAWBOT_DEFAULT_TARGET,
-            WECHATCLAWBOT_ADMINS=WECHATCLAWBOT_ADMINS,
-            WECHATCLAWBOT_POLL_TIMEOUT=WECHATCLAWBOT_POLL_TIMEOUT,
-            auto_start_polling=False,
-        )
-
-    @classmethod
     def get_wechatclawbot_client(
-            cls,
+            self,
             source: Optional[str] = None,
             fallback_source: Optional[str] = None,
             WECHATCLAWBOT_BASE_URL: Optional[str] = None,
@@ -1887,32 +1863,20 @@ class MessageChain(ChainBase):
             allow_temporary: bool = False,
     ):
         """获取已加载的微信 ClawBot 客户端，必要时退回到临时客户端。"""
-        module = ModuleManager().get_running_module("WechatClawBotModule")
         source_name = str(source or "").strip() or None
-        fallback_name = str(fallback_source or "").strip() or None
 
-        if module:
-            candidate_names = []
-            for candidate in (fallback_name, source_name):
-                if candidate and candidate not in candidate_names:
-                    candidate_names.append(candidate)
-
-            if candidate_names:
-                for candidate in candidate_names:
-                    config = module.get_config(candidate)
-                    if not config:
-                        continue
-                    client = module.get_instance(config.name)
-                    if client:
-                        return client, None
-            else:
-                client = module.get_instance()
-                if client:
-                    return client, None
+        client = self.run_module(
+            "wechatclawbot_client",
+            source=source,
+            fallback_source=fallback_source,
+        )
+        if client:
+            return client, None
 
         if allow_temporary:
-            temp_client = cls._build_wechatclawbot_temp_client(
-                source=source_name or fallback_name,
+            temp_client = self.run_module(
+                "wechatclawbot_temp_client",
+                source=source_name or str(fallback_source or "").strip() or None,
                 WECHATCLAWBOT_BASE_URL=WECHATCLAWBOT_BASE_URL,
                 WECHATCLAWBOT_DEFAULT_TARGET=WECHATCLAWBOT_DEFAULT_TARGET,
                 WECHATCLAWBOT_ADMINS=WECHATCLAWBOT_ADMINS,
@@ -1925,15 +1889,16 @@ class MessageChain(ChainBase):
             return None, f"未找到名为 {source_name} 的微信 ClawBot 通知配置"
         return None, "微信 ClawBot 通知未启用或配置尚未保存，请先保存并启用当前渠道"
 
-    @staticmethod
     def migrate_wechatclawbot_cache(
+            self,
             old_name: str,
             new_name: str,
             cleanup_old: bool = False,
             overwrite: bool = False,
     ):
         """在通知名称变更时迁移对应的微信 ClawBot 登录缓存。"""
-        return WechatClawBot.migrate_cached_state(
+        return self.run_module(
+            "wechatclawbot_migrate_cache",
             old_name=old_name,
             new_name=new_name,
             cleanup_old=cleanup_old,