feat: Implement OAuth2 authentication with Google and GitHub

- Added OAuth2 endpoints for Google and GitHub authentication.
- Created OAuth service to handle provider interactions and user info retrieval.
- Implemented user OAuth repository for managing user OAuth links in the database.
- Updated auth service to support linking existing users and creating new users via OAuth.
- Added CORS middleware to allow frontend access.
- Created tests for OAuth endpoints and service functionality.
- Introduced environment configuration for OAuth client IDs and secrets.
- Added logging for OAuth operations and error handling.

app/api/v1/auth.py

@@ -54,8 +54,6 @@ async def register(
             samesite=settings.COOKIE_SAMESITE,
         )
 
-        # Return only user data, tokens are now in cookies
-        return auth_response.user
     except HTTPException:
         raise
     except Exception as e:
@@ -64,6 +62,8 @@ async def register(
             status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
             detail="Registration failed",
         ) from e
+    else:
+        return auth_response.user
 
 
 @router.post("/login")
@@ -101,8 +101,6 @@ async def login(
             samesite=settings.COOKIE_SAMESITE,
         )
 
-        # Return only user data, tokens are now in cookies
-        return auth_response.user
     except HTTPException:
         raise
     except Exception as e:
@@ -111,6 +109,8 @@ async def login(
             status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
             detail="Login failed",
         ) from e
+    else:
+        return auth_response.user
 
 
 @router.get("/me")
@@ -156,7 +156,6 @@ async def refresh_token(
             samesite=settings.COOKIE_SAMESITE,
         )
 
-        return {"message": "Token refreshed successfully"}
     except HTTPException:
         raise
     except Exception as e:
@@ -165,6 +164,8 @@ async def refresh_token(
             status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
             detail="Token refresh failed",
         ) from e
+    else:
+        return {"message": "Token refreshed successfully"}
 
 
 @router.post("/logout")
@@ -176,7 +177,7 @@ async def logout(
 ) -> dict[str, str]:
     """Logout endpoint - clears cookies and revokes refresh token."""
     user = None
-    
+
     # Try to get user from access token first
     if access_token:
         try:
@@ -188,7 +189,7 @@ async def logout(
                 logger.info("Found user from access token: %s", user.email)
         except (HTTPException, Exception) as e:
             logger.info("Access token validation failed: %s", str(e))
-    
+
     # If no user found, try refresh token
     if not user and refresh_token:
         try:
@@ -200,14 +201,14 @@ async def logout(
                 logger.info("Found user from refresh token: %s", user.email)
         except (HTTPException, Exception) as e:
             logger.info("Refresh token validation failed: %s", str(e))
-    
+
     # If we found a user, revoke their refresh token
     if user:
         await auth_service.revoke_refresh_token(user)
         logger.info("Successfully revoked refresh token for user: %s", user.email)
     else:
         logger.info("No user found, skipping token revocation")
-    
+
     # Always clear both cookies regardless of token validity
     response.delete_cookie(
         key="access_token",
@@ -221,5 +222,5 @@ async def logout(
         secure=settings.COOKIE_SECURE,
         samesite=settings.COOKIE_SAMESITE,
     )
-    
+
     return {"message": "Successfully logged out"}