feat: M4 文风 + M5 生成/多provider/Skill + Kimi Code 订阅接入 + 本地联调修复

M4（文风）: style-auditor 双轨（提取指纹/漂移第四审）+ jobs 长任务框架(zombie reaper) + 回炉 refine + GET /style read-back。
M5（生成+扩展）: worldbuilder/character-gen（入库 continuity 409 gate + partition_writes 白名单 + schema→JSONB 形变）；
  网关多 provider 回退链/熔断/能力降级（Anthropic/Gemini 适配器）；Skill registry + 表权限沙箱 + 规则；
  前端 角色生成器/世界观/Codex/规则页/技能库/⌘K 命令面板。
K1（Kimi Code 订阅接入）: OAuth device-flow（kimi-code）+ 静态 Console key（kimi-code-key）两路径；
  coding 端点 KimiCLI 伪造头（实测 UA allow-list 门禁，缺则 403）+ JSON 模式结构化（thinking ⊥ tool_choice）。
本地联调修复: CORS 中间件；assemble 注入 premise+「写第N章」指令（修空 prompt 400）；
  GET /outline·/draft read-back + 大纲/工作台/审稿页重载；写页 client/server 常量边界 + notFound 健壮化；
  字数 toLocaleString locale 水合；审稿页终稿从已存草稿 seed（修 accept 422）。
门禁: backend ruff/mypy(157)/alembic 无漂移/pytest 451 · frontend lint/tsc/vitest/build。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/api/tests/fakes_providers.py

@@ -15,21 +15,34 @@ class FakeCredentialStore:
     """实现 `CredentialStore` Protocol 的内存版。"""
 
     def __init__(self) -> None:
-        # key: (owner_id, provider) → 密文
+        # key: (owner_id, provider) → api_key 密文
         self.creds: dict[tuple[uuid.UUID, str], bytes] = {}
+        # key: (owner_id, provider) → oauth 密文（OAuth 凭据，auth_type="oauth"）
+        self.oauth: dict[tuple[uuid.UUID, str], bytes] = {}
         self.routing: dict[str, StoredRouting] = {}
 
     async def list_credentials(self, owner_id: uuid.UUID) -> list[StoredCredential]:
-        return [
+        rows = [
             StoredCredential(provider=p, api_key_enc=blob)
             for (o, p), blob in self.creds.items()
             if o == owner_id
         ]
+        rows += [
+            StoredCredential(provider=p, api_key_enc=None, auth_type="oauth", oauth_enc=blob)
+            for (o, p), blob in self.oauth.items()
+            if o == owner_id
+        ]
+        return rows
 
     async def list_routing(self) -> list[StoredRouting]:
         return list(self.routing.values())
 
     async def get_credential(self, owner_id: uuid.UUID, provider: str) -> StoredCredential | None:
+        oauth_blob = self.oauth.get((owner_id, provider))
+        if oauth_blob is not None:
+            return StoredCredential(
+                provider=provider, api_key_enc=None, auth_type="oauth", oauth_enc=oauth_blob
+            )
         blob = self.creds.get((owner_id, provider))
         if blob is None:
             return None
@@ -39,6 +52,19 @@ class FakeCredentialStore:
         self, owner_id: uuid.UUID, provider: str, api_key_enc: bytes
     ) -> None:
         self.creds[(owner_id, provider)] = api_key_enc
+        self.oauth.pop((owner_id, provider), None)
+
+    async def upsert_oauth_credential(
+        self, owner_id: uuid.UUID, provider: str, oauth_enc: bytes
+    ) -> None:
+        self.oauth[(owner_id, provider)] = oauth_enc
+        self.creds.pop((owner_id, provider), None)
+
+    async def delete_credential(self, owner_id: uuid.UUID, provider: str) -> bool:
+        had = (owner_id, provider) in self.creds or (owner_id, provider) in self.oauth
+        self.creds.pop((owner_id, provider), None)
+        self.oauth.pop((owner_id, provider), None)
+        return had
 
     async def upsert_routing(self, routing: StoredRouting) -> None:
         self.routing[routing.tier] = routing