Bring the self-hosting guides in line with the shipped code

- geolite2: quote the real commented compose mount (./geolite2 to
  /opt/geolite2, the GEOLITE2_DIR default, so no env var is needed for
  the default path)
- getting-started: healthcheck probes /api/health, not /api/version;
  the environment module reaches archive-api and geocoding-api
  .open-meteo.com, relevant for egress allowlists
- mcp: the module is opt-in and off by default, but no longer the only
  such module
- reverse-proxy: the Coach stream is SSE over plain HTTP, not
  WebSockets; note that TRUST_PROXY_HOPS is not on the bundled compose
  whitelist and must be added by hand
- scaling: /api/health healthcheck; worker liveness is in-memory and
  invisible across a web/worker split; pool sizing now goes through
  getConnectionBudget with DB_CONNECTION_LIMIT as the compose knob and
  a 2-connection pg-boss share
- sso: the native SSO handoff shipped, OIDC_ONLY works with app builds
  that carry it
- unraid: geo databases are baked in only when the build had a licence
  key, or mounted; replaceable either way

docs/self-hosting/unraid.md

@@ -7,7 +7,8 @@ Unraid UI, but because CA templates describe a single container you install
 PostgreSQL separately and wire the two together.
 
 HealthLog stores all persistent state in PostgreSQL — the app container itself is
-stateless (the offline geo-IP databases are baked into the image). A backup of
+stateless (the offline geo-IP databases are either baked in at build time or
+mounted read-only; replaceable either way, not state). A backup of
 the database is a backup of everything.
 
 ## What you need