refactor: 用 EndpointFetchConfig 纯数据类替代 ORM 对象传递，统一上游模型缓存管理

- 引入 EndpointFetchConfig dataclass 替代直接传递 ProviderEndpoint ORM 对象，
  避免 DB session 关闭后 DetachedInstanceError
- 新增 build_format_to_config() 统一构建 api_format -> EndpointFetchConfig 映射
- KeyAllowedModelsDialog 改用 useUpstreamModelsCache composable 管理上游模型获取
- useUpstreamModelsCache 增加 error 字段透传部分格式获取失败的 warning
- 删除废弃的 queryProviderUpstreamModels API 函数
- ProviderCandidate 添加 __lt__ 方法支持排序比较

src/api/admin/provider_query.py

@@ -27,7 +27,9 @@ from src.services.model.fetch_scheduler import (
     set_upstream_models_to_cache,
 )
 from src.services.model.upstream_fetcher import (
+    EndpointFetchConfig,
     UpstreamModelsFetchContext,
+    build_format_to_config,
     fetch_models_for_key,
     get_adapter_for_format,
 )
@@ -171,11 +173,8 @@ async def query_available_models(
     if not provider:
         raise HTTPException(status_code=404, detail="Provider not found")
 
-    # 构建 api_format -> endpoint 映射
-    format_to_endpoint: dict[str, ProviderEndpoint] = {}
-    for endpoint in provider.endpoints:
-        if endpoint.is_active:
-            format_to_endpoint[endpoint.api_format] = endpoint
+    # 构建 api_format -> EndpointFetchConfig 映射（纯数据，不依赖 ORM session）
+    format_to_endpoint = build_format_to_config(provider.endpoints)
 
     if not format_to_endpoint:
         raise HTTPException(status_code=400, detail="No active endpoints found for this provider")
@@ -327,7 +326,7 @@ def _aggregate_models_by_id(models: list[dict]) -> list[dict]:
 async def _fetch_models_for_single_key(
     provider: Provider,
     api_key_id: str,
-    format_to_endpoint: dict[str, ProviderEndpoint],
+    format_to_endpoint: dict[str, EndpointFetchConfig],
     force_refresh: bool,
 ) -> Any:
     """获取单个 Key 的模型列表"""

src/plugins/load_balancer/base.py

@@ -28,6 +28,16 @@ class ProviderCandidate:
         if self.metadata is None:
             self.metadata = {}
 
+    def __lt__(self, other: object) -> bool:
+        if not isinstance(other, ProviderCandidate):
+            return NotImplemented
+        # 优先级数字越大越优先，权重越大越优先
+        return (-self.priority, -self.weight, str(getattr(self.provider, "id", ""))) < (
+            -other.priority,
+            -other.weight,
+            str(getattr(other.provider, "id", "")),
+        )
+
 
 @dataclass
 class SelectionResult:

src/services/model/fetch_scheduler.py

@@ -28,7 +28,9 @@ from src.core.provider_types import ProviderType
 from src.database import create_session
 from src.models.database import Provider, ProviderAPIKey
 from src.services.model.upstream_fetcher import (
+    EndpointFetchConfig,
     UpstreamModelsFetchContext,
+    build_format_to_config,
     fetch_models_for_key,
     merge_upstream_metadata,
 )
@@ -62,7 +64,7 @@ class PreparedModelsFetchContext:
     auth_type: str
     encrypted_api_key: str
     encrypted_auth_config: str | None
-    format_to_endpoint: dict[str, Any]
+    format_to_endpoint: dict[str, EndpointFetchConfig]
     proxy_config: dict[str, Any] | None
 
 
@@ -422,11 +424,8 @@ class ModelFetchScheduler:
                 db.commit()
                 return "error"
 
-            # 构建 api_format -> endpoint 映射
-            format_to_endpoint: dict[str, Any] = {}
-            for endpoint in provider.endpoints:  # type: ignore[attr-defined]
-                if endpoint.is_active:
-                    format_to_endpoint[endpoint.api_format] = endpoint
+            # 构建 api_format -> EndpointFetchConfig 映射（纯数据，session 无关）
+            format_to_endpoint = build_format_to_config(provider.endpoints)  # type: ignore[attr-defined]
 
             if not format_to_endpoint:
                 logger.warning(f"Provider {provider.name} 没有活跃的端点，跳过 Key {key.id}")

src/services/model/upstream_fetcher.py

@@ -7,6 +7,7 @@
 """
 
 import asyncio
+from collections.abc import Iterable
 from dataclasses import dataclass
 from typing import Any, Awaitable, Callable
 
@@ -14,7 +15,6 @@ import httpx
 
 from src.core.api_format import get_extra_headers_from_endpoint
 from src.core.logger import logger
-from src.models.database import ProviderEndpoint
 from src.utils.ssl_utils import get_ssl_context
 
 # 并发请求限制
@@ -35,13 +35,42 @@ _ModelsFetcher = Callable[
 ]
 
 
+@dataclass(frozen=True, slots=True)
+class EndpointFetchConfig:
+    """端点获取配置（纯数据，不依赖 DB session）。
+
+    从 ProviderEndpoint ORM 对象提取必要字段，确保在 DB session 关闭后
+    仍可安全使用（避免 DetachedInstanceError）。
+    """
+
+    base_url: str
+    extra_headers: dict[str, str] | None = None
+
+
+def build_format_to_config(endpoints: Iterable[Any]) -> dict[str, EndpointFetchConfig]:
+    """将活跃的 ProviderEndpoint 转换为 api_format -> EndpointFetchConfig 映射。
+
+    应在 DB session 活跃时调用，提取 ORM 对象上的 base_url 和 header_rules，
+    转换为 session 无关的纯数据结构。
+    """
+    result: dict[str, EndpointFetchConfig] = {}
+    for ep in endpoints:
+        if not getattr(ep, "is_active", False):
+            continue
+        result[ep.api_format] = EndpointFetchConfig(
+            base_url=ep.base_url,
+            extra_headers=get_extra_headers_from_endpoint(ep),
+        )
+    return result
+
+
 @dataclass(frozen=True)
 class UpstreamModelsFetchContext:
     """上游模型获取上下文（Key 级别）。"""
 
     provider_type: str
     api_key_value: str
-    format_to_endpoint: dict[str, Any]
+    format_to_endpoint: dict[str, EndpointFetchConfig]
     proxy_config: dict[str, Any] | None = None
     auth_config: dict[str, Any] | None = None
 
@@ -149,7 +178,7 @@ def get_adapter_for_format(api_format: str) -> type | None:
 
 def build_all_format_configs(
     api_key_value: str,
-    format_to_endpoint: dict[str, ProviderEndpoint],
+    format_to_endpoint: dict[str, EndpointFetchConfig],
 ) -> list[dict]:
     """
     构建所有 API 格式的端点配置
@@ -159,7 +188,7 @@ def build_all_format_configs(
 
     Args:
         api_key_value: 解密后的 API Key
-        format_to_endpoint: API 格式到端点的映射
+        format_to_endpoint: API 格式到 EndpointFetchConfig 的映射
 
     Returns:
         端点配置列表，每个配置包含 api_key, base_url, api_format, extra_headers
@@ -172,13 +201,13 @@ def build_all_format_configs(
     for candidates in MODEL_FETCH_FORMAT_PRIORITY:
         fmt = next((f for f in candidates if f in format_to_endpoint), None)
         if fmt is not None:
-            ep = format_to_endpoint[fmt]
+            cfg = format_to_endpoint[fmt]
             configs.append(
                 {
                     "api_key": api_key_value,
-                    "base_url": ep.base_url,
+                    "base_url": cfg.base_url,
                     "api_format": fmt,
-                    "extra_headers": get_extra_headers_from_endpoint(ep),
+                    "extra_headers": cfg.extra_headers,
                 }
             )
     return configs