feat(#875): LLM Router shadow mode + consolidate litellm master key

backend/python/app/api/chat_service.py

@@ -193,6 +193,23 @@ from ..middleware.log_service import LogService
 
 
 from ..capability_registry import resolve_auto_model
+try:
+    from ..core.llm_router import (
+        resolve_api_key as _llm_resolve_api_key,
+        route as _llm_route,
+        set_route_ctx as _set_route_ctx,
+        SHADOW as _LLM_ROUTER_SHADOW,
+    )
+except Exception as _llm_router_err:
+    import os as _os, logging as _logging
+    _logging.getLogger(__name__).warning(f"[chat] llm_router import failed, router disabled: {_llm_router_err}")
+    def _llm_resolve_api_key(api_url, model_api_key, provider_api_key):
+        if api_url and "qihu-aiflow-litellm" in api_url:
+            return _os.environ.get("LITELLM_MASTER_KEY") or "sk-litellm-master-key-aiflow-2026"
+        return model_api_key or provider_api_key
+    _llm_route = None
+    _set_route_ctx = None
+    _LLM_ROUTER_SHADOW = True
 
 
 
@@ -2820,6 +2837,16 @@ async def _send_message_core(
 
         _try_models.extend([m for m in _fallbacks if m not in _try_models])
 
+    # ===== LLM Router（#875 影子模式）=====
+    try:
+        if _llm_route is not None:
+            _set_route_ctx(tenant_id=getattr(current_user, "tenant_id", "") or "", claw_type="web")
+            _rm = _llm_route("text", db=db, legacy_primary=_try_models[0].name if _try_models else None)
+            if not _LLM_ROUTER_SHADOW and _rm.models:
+                _try_models = _rm.models
+    except Exception as _e:
+        logger.warning(f"[chat] LLM Router 观测失败(降级忽略): {_e}")
+
     _retry_log = []
 
     _all_failed = False
@@ -3082,8 +3109,8 @@ async def _send_message_core(
 
                 # 2026-07-29 fix: 调用 LiteLLM 端点时，必须用 master key (sk-litellm-...) 而非模型自身 key (tp-c...)
                 # LiteLLM 内置每个 model 的真实 key 在 litellm_config.yaml，chat 不应直接传模型的 key
+                api_key = _llm_resolve_api_key(api_url, api_key, provider.api_key if provider else None)
                 if api_url and "qihu-aiflow-litellm" in api_url:
-                    api_key = os.environ.get("LITELLM_MASTER_KEY") or "sk-litellm-master-key-aiflow-2026"
                     auth_header = None  # 用默认 Authorization: Bearer
                     logger.info("[chat] LiteLLM endpoint detected, using master key instead of model key")