check_dingtalk_requirements() used 'and' to check for missing env vars:
if not CLIENT_ID and not CLIENT_SECRET: return False
This only returns False when BOTH are missing. If only one is set
(e.g. CLIENT_ID without CLIENT_SECRET), the check passes and
connect() fails later with a cryptic error.
Fix: Change 'and' to 'or' so it returns False when EITHER is missing.
a9da944a5d