refactor: Update response types to use common schemas across API endpoints

app/api/v1/main.py

@@ -3,6 +3,7 @@
 from fastapi import APIRouter
 
 from app.core.logging import get_logger
+from app.schemas.common import HealthResponse
 
 router = APIRouter()
 
@@ -10,7 +11,7 @@ logger = get_logger(__name__)
 
 
 @router.get("/")
-def health() -> dict[str, str]:
+def health() -> HealthResponse:
     """Health check endpoint."""
     logger.info("Health check endpoint accessed")
-    return {"status": "healthy"}
+    return HealthResponse(status="healthy")