- URL-encodes the OAuth error message when constructing the redirect URL in the OIDC callback handler
- Without encoding, error messages containing spaces, ampersands, or other special characters produce malformed URLs that the frontend cannot parse correctly
- The custom OAuth client callback handler already correctly uses urllib.parse.quote_plus() for the same purpose; this fix brings the OIDC handler in line with that pattern
Co-authored-by: gambletan <tan@gambletan.com>
