feat: implement AI model API proxy service

backend/app/models/request_log.py

@@ -0,0 +1,18 @@
+"""Request log model."""
+from dataclasses import dataclass
+from typing import Optional
+
+
+@dataclass
+class RequestLog:
+    """Request log entry."""
+    id: Optional[int]
+    client_key_id: int
+    provider_id: int
+    model: str
+    prompt_tokens: Optional[int]
+    completion_tokens: Optional[int]
+    latency_ms: Optional[int]
+    success: bool
+    error_message: Optional[str]
+    created_at: Optional[str]