feat: add Pydantic models for match requests and responses

Author: SherwynNg

services/matching-service/app/models/match.py

@@ -0,0 +1,14 @@
+from pydantic import BaseModel
+from typing import Optional
+
+class MatchRequest(BaseModel):
+    user_id: str
+    difficulty: str
+    topic: str
+    language: str
+
+class MatchResponse(BaseModel):
+    success: bool
+    peer_id: Optional[str] = None
+    # queue_position: Optional[int] = None
+    message: Optional[str] = None