Replace python-jose with PyJWT and update its usage.

Switched the dependency from `python-jose` to `PyJWT` to handle JWT encoding and decoding. Updated related code to use `PyJWT`'s `InvalidTokenError` instead of `JWTError`. Also bumped the application version from `0.1.7` to `0.1.8`.

backend/app/api/routes/auth.py

@@ -1,5 +1,5 @@
 from fastapi import APIRouter, Depends, HTTPException, status
-from jose import JWTError, jwt
+import jwt
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 from app.core.config import get_settings
@@ -29,7 +29,7 @@ async def login(payload: LoginRequest, db: AsyncSession = Depends(get_db)) -> To
 async def refresh(payload: RefreshRequest, db: AsyncSession = Depends(get_db)) -> TokenResponse:
     try:
         token_payload = jwt.decode(payload.refresh_token, settings.jwt_secret_key, algorithms=[settings.jwt_algorithm])
-    except JWTError as exc:
+    except jwt.InvalidTokenError as exc:
         raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid refresh token") from exc
 
     if token_payload.get("type") != "refresh":