feat(api): add ppy-compatible error response

main.py

@@ -19,8 +19,9 @@ from app.router import (
 from app.service.daily_challenge import daily_challenge_job
 from app.service.osu_rx_statistics import create_rx_statistics
 
-from fastapi import FastAPI
+from fastapi import FastAPI, HTTPException, Request
 from fastapi.middleware.cors import CORSMiddleware
+from fastapi.responses import JSONResponse
 
 
 @asynccontextmanager
@@ -67,6 +68,13 @@ async def health_check():
     return {"status": "ok", "timestamp": datetime.utcnow().isoformat()}
 
 
+@app.exception_handler(HTTPException)
+async def http_exception_handler(request: Request, exc: HTTPException):
+    if request.url.path.startswith("/api/v2"):
+        return JSONResponse(status_code=exc.status_code, content={"error": exc.detail})
+    raise exc
+
+
 if settings.secret_key == "your_jwt_secret_here":
     logger.warning(
         "jwt_secret_key is unset. Your server is unsafe. "