Fix workspace detail races and provider default handling

Keep analysis and Skill detail responses bound to the selected request, reject stale publish confirmations, and clear failed position-history results with retry controls.

Reject removal of the current default provider with HTTP 409 and reflect that contract in the form. Track the OpenAPI page and API module by restricting the docs ignore rule to the repository root.

Validate the staged provider contract with four isolated tests. Reuse the matching candidate's frontend lint, type check, 26 test groups, and production build results.

backend/src/alphapulse/api/settings.py

@@ -67,6 +67,7 @@ class ProviderPatch(BaseModel):
     context_window: Annotated[int | None, Field(ge=4096, le=2000000)] = None
     # 显式传 null 表示不传思考强度
     reasoning_effort: llm.Effort | None = None
+    # 只能将另一模型设为默认，不能直接取消当前默认模型。
     is_default: bool | None = None
 
 
@@ -120,6 +121,8 @@ async def create_provider(body: ProviderIn, session: Annotated[AsyncSession, Dep
 @router.patch("/providers/{provider_id}")
 async def patch_provider(provider_id: int, body: ProviderPatch, session: Annotated[AsyncSession, Depends(get_session)]) -> ApiResponse[ProviderOut]:
     provider = await get_provider(session, provider_id)
+    if body.is_default is False and provider.is_default:
+        raise HTTPException(status.HTTP_409_CONFLICT, "不能直接取消默认模型，请将其他模型设为默认")
     values = body.model_dump(exclude_unset=True, exclude={"api_key", "base_url", "is_default"})
     # reasoning_effort 显式传 null 表示清除，其他字段为 null 时忽略
     for field, value in values.items():