Extends the shipped CFG_MASTER_DIRECTORY_URL/JOIN_KEY join flow with the
selfUrl a spoke needs to register itself for live catalog replication
(theta-directory v2.4.0's POST /api/site/spokes) -- without this, every
spoke was permanently limited to the one-time join snapshot even after
the master gained the ability to push live updates.
setup.sh already computes CFG_SSO_HOST before this point in the script;
passes https://$CFG_SSO_HOST as bootstrap/site-join.js's third argument,
which forwards it as `selfUrl` in the POST /api/site/join body.
Multi-site join wiring (server + UI landed in theta-directory v2.3.0):
- bootstrap/site-join.js: runs inside the sso-manager container (same
self-contained rule as bootstrap.js); logs in as the bootstrap admin and calls
/api/site/join. Idempotent: an already-joined node reports 'already a spoke'.
- setup.sh step 5b: if setup.env sets CFG_MASTER_DIRECTORY_URL +
CFG_MASTER_DIRECTORY_JOIN_KEY, run the join after the bootstrap. Only honored
on first run (ensure_config reads setup.env once and ignores it once
./config/ exists), so an already-populated directory can never be merged.
- setup.env.example documents both vars.
- lint.yml also node --check's site-join.js.
wmantly