feat: FastAPI Exception Handler 추가

에러 발생시 대략적으로 어떤 에러인지 메시지 리턴

src/backend/main.py

@@ -1,6 +1,13 @@
 from fastapi import FastAPI
+from fastapi.responses import JSONResponse
 from fastapi.middleware.cors import CORSMiddleware
-from backend.routers import txt_extraction, machine_translation, untypical_txt_extraction, untypical_machine_translation, untypical_generation
+from backend.routers import (
+    txt_extraction,
+    machine_translation,
+    untypical_txt_extraction,
+    untypical_machine_translation,
+    untypical_generation,
+)
 
 app = FastAPI()
 
@@ -20,3 +27,8 @@
 app.include_router(untypical_txt_extraction.router)
 app.include_router(untypical_machine_translation.router)
 app.include_router(untypical_generation.router)
+
+
+@app.exception_handler(Exception)
+async def exception_handler(request, exc):
+    return JSONResponse(status_code=500, content={"message": str(exc)})