refactor: 全局适配 ApiFamily/EndpointKind 结构化标识体系

将新的 (ApiFamily, EndpointKind) / `family:kind` 签名体系应用到整个代码库：
- API Handlers: 所有 adapter/handler 使用新的签名格式
- Services: provider, model, usage, cache, auth 等服务层适配
- Database: ProviderEndpoint 新增 api_family/endpoint_kind 字段
- Frontend: Provider 管理、Usage 表格等组件适配
- Tests: 更新所有相关测试用例

tests/api/handlers/base/test_stream_processor.py

@@ -1,6 +1,11 @@
 from typing import Any
 
-from src.api.handlers.base.response_parser import ParsedChunk, ParsedResponse, ResponseParser, StreamStats
+from src.api.handlers.base.response_parser import (
+    ParsedChunk,
+    ParsedResponse,
+    ResponseParser,
+    StreamStats,
+)
 from src.api.handlers.base.stream_context import StreamContext
 from src.api.handlers.base.stream_processor import StreamProcessor
 from src.utils.sse_parser import SSEEventParser
@@ -21,7 +26,7 @@ class DummyParser(ResponseParser):
 
 
 def test_process_line_strips_newlines_and_finalizes_event() -> None:
-    ctx = StreamContext(model="test-model", api_format="OPENAI")
+    ctx = StreamContext(model="test-model", api_format="openai:chat")
     processor = StreamProcessor(request_id="test-request", default_parser=DummyParser())
     sse_parser = SSEEventParser()
 
@@ -29,4 +34,3 @@ def test_process_line_strips_newlines_and_finalizes_event() -> None:
     processor._process_line(ctx, sse_parser, "\n")
 
     assert ctx.has_completion is True
-