refactor: optimize middleware with pure ASGI implementation and enhance security measures

- Replace BaseHTTPMiddleware with pure ASGI implementation in plugin middleware for better streaming response handling
- Add trusted proxy count configuration for client IP extraction in reverse proxy environments
- Implement audit log cleanup scheduler with configurable retention period
- Replace plaintext token logging with SHA256 hash fingerprints for security
- Fix database session lifecycle management in middleware
- Improve request tracing and error logging throughout the system
- Add comprehensive tests for pipeline architecture

src/api/handlers/base/cli_handler_base.py

@@ -532,7 +532,7 @@ class CliMessageHandlerBase(BaseMessageHandler):
             async for chunk in stream_response.aiter_raw():
                 # 在第一次输出数据前更新状态为 streaming
                 if not streaming_status_updated:
-                    self._update_usage_to_streaming(ctx.request_id)
+                    self._update_usage_to_streaming_with_ctx(ctx)
                     streaming_status_updated = True
 
                 buffer += chunk
@@ -816,7 +816,7 @@ class CliMessageHandlerBase(BaseMessageHandler):
 
             # 在第一次输出数据前更新状态为 streaming
             if prefetched_chunks:
-                self._update_usage_to_streaming(ctx.request_id)
+                self._update_usage_to_streaming_with_ctx(ctx)
 
             # 先处理预读的字节块
             for chunk in prefetched_chunks: