The config loader now searches multiple paths for sms-sites.json
(REPO_ROOT-based, /app/, and CWD-relative) so it works regardless
of deployment environment. When config can't be loaded, the auth
check fails open (allows messages through) rather than blocking
everything. The isOwnNumber check still returns false when config
is unavailable since we can't identify our own numbers without it.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>