docs: fix stale multi-site claims, document LDAP MMR auto-config + CFG_PUBLIC_DOMAIN

The published docs site had drifted from what actually shipped:

- docs/sso/multi-site.md said the no-inbound relay was "designed but
  not automated" -- it's been automated since earlier this session.
  Also said "don't combine" multi-site join and LDAP replication --
  they're integrated now (join auto-configures LDAP MMR).
- docs/sso/replication.md (the actually-published/linked replication
  page -- distinct from theta-directory's own docs/replication.md,
  which isn't linked from this site's nav at all) still only described
  the old fully-manual LDAP_SERVER_ID/LDAP_REPLICATION_HOSTS setup,
  with zero mention of the new auto-config or CFG_LDAP_MMR_MANUAL.
- docs/index.md's feature bullet described multi-site purely as "N-Way
  Multi-Master LDAP replication" -- the actual master/spoke join
  feature (the more commonly-used, higher-level mechanism) wasn't
  mentioned on the homepage at all.
- CFG_PUBLIC_DOMAIN (shipped, never documented anywhere an operator
  would read it) now explained in multi-site.md.
- spoke.env now discoverable from quickstart.md, not just multi-site.md.

Also documents the real, load-bearing limitation from this session's
promotion/LDAP-orphan fix: the master's own replication peer list only
updates on its own next setup.sh run, not live the instant a spoke
joins or a promotion happens.

docs/index.md

@@ -74,10 +74,12 @@ The SSO Manager and the proxy it fronts, both stood up by one `./setup.sh` run:
   management built directly into the web interface, allowing operators to drive
   system administration and automation pipelines programmatically without an
   active browser session.
-- **Multi-Site Geo-Replication**: Built-in support for N-Way Multi-Master LDAP
+- **Multi-Site Geo-Replication**: A master site and any number of spokes join
-  replication, allowing directory states to sync across geographically separated
+  with one key and one URL, staying in sync automatically (no manual LDAP
-  physical hardware or remote data centers for high availability and low-latency
+  config) — see [Multi-Site (Master/Spoke Join)](sso/multi-site.html). Raw
-  local reads.
+  N-Way Multi-Master LDAP replication is also available directly for
+  deployments that want every site independently writable with no
+  master/spoke concept — see [Geo-Location Scaling](sso/replication.html).
 - **Multi-Target Load Balancing**: Native reverse-proxy load balancing that
   distributes traffic across multiple application backends using customizable
   health checks and round-robin strategies.

docs/quickstart.md

@@ -74,6 +74,11 @@ file shape.
 > exist, `./setup.sh` migrates them into `./config/` preserving your existing
 > secrets — no need to write a `setup.env`.
 
+> **Joining an existing Theta Directory cluster instead of seeding a fresh
+> one?** See [Multi-Site (Master/Spoke Join)](sso/multi-site.html) —
+> `spoke.env.example` has the join-a-cluster vars split out into their own
+> file, or set them directly in `setup.env` (which has every option).
+
 ---
 
 ## 3. Run

docs/sso/multi-site.md

@@ -10,10 +10,10 @@ the **master** (single write authority for the shared catalog) and any
 number of **spokes** — read-only replicas that stay in sync automatically and
 run local authentication with zero WAN dependency.
 
-This is a different, higher-level mechanism than [raw LDAP N-way
+This is a higher-level mechanism than [raw LDAP N-way
-replication](replication.html) — see [How this relates to LDAP
+replication](replication.html) — and it now drives that lower-level
-replication](#how-this-relates-to-ldap-replication) below if you're deciding
+replication for you automatically. See [How this relates to LDAP
-between the two.
+replication](#how-this-relates-to-ldap-replication) below.
 
 ## Why and when to use this
 
@@ -45,6 +45,13 @@ between the two.
      stack's setup. Both are read; `spoke.env`'s values win on a conflict.
      No public IP on this site at all? `spoke.env.example` also covers the
      no-inbound relay vars (`CFG_SPOKE_NO_INBOUND`/`CFG_SPOKE_PUBLIC_HOST`).
+
+     Want this spoke reachable at its own public domain rather than sharing
+     the master's? `CFG_DOMAIN` (the LDAP identity namespace) must stay
+     identical across every site in a cluster — MMR replicas can't diverge
+     on base DN — but `CFG_PUBLIC_DOMAIN` overrides just this site's own web
+     hostnames (`sso.*`/`proxy.*`) independently of it. Only meaningful for
+     an inbound spoke serving its own traffic directly.
 3. The spoke pulls the master's full export (LDAP tree, resource catalog,
    agent-signing key) and adopts it, then registers its own reachable URL
    with the master so it can receive live updates going forward.
@@ -82,26 +89,44 @@ so on) are **not** currently synced — each site still generates its own.
 
 - Both sites need a network path to each other's HTTP(S) API — the master to
   pull an export from, the spoke to push replication updates back to. A site
-  with no inbound path at all (e.g. behind CGNAT) can't join yet on its own;
+  with **no inbound path at all** (e.g. behind CGNAT) can still join: set
-  a relay mechanism for that case is designed but not automated (see the
+  `CFG_SPOKE_NO_INBOUND=true` + `CFG_SPOKE_PUBLIC_HOST` (`spoke.env.example`)
-  [architecture spec](https://github.com/theta42/theta-suite/blob/master/docs/MULTI_SITE_SPEC.md)
+  once its jump-host is meshed to the master's over WireGuard (mesh peering
-  for the current status).
+  itself is a manual, one-time step on both jump-hosts — see [Theta Gateway
+  → Mesh](../jump-host/mesh.html)) — the master then relays traffic to it
+  and auto-creates the matching route on its own `theta-proxy`. A spoke with
+  **zero inbound and zero outbound** path still can't join at all (the join
+  itself needs to reach the master's API directly).
 - Joining only ever happens on a **fresh install**. There's no way to merge
   an already-populated directory into a master's — re-provision the host
   first.
+- Promoting a spoke to master doesn't instantly finish reconciling OpenLDAP
+  replication (see below) — re-run `setup.sh` on the newly-promoted node
+  promptly afterward.
 
 ## How this relates to LDAP replication
 
-[N-way LDAP replication](replication.html) is a *lower-level*, different
+[N-way LDAP replication](replication.html) is the *lower-level* mechanism
-mechanism: every site runs a fully independent, fully writable `slapd`, wired
+underneath this: `slapd`'s own `syncrepl`, wired via `LDAP_SERVER_ID` +
-together with raw `syncrepl` environment variables, and there's no concept of
+`LDAP_REPLICATION_HOSTS`. Originally this was hand-configured by the
-a master or a managed join. It predates this feature and is still there for
+operator, separately from the join flow above, for deployments that wanted
-deployments that specifically want every site independently writable.
+every site independently writable with no concept of a master.
 
-Multi-site join (this page) is the opposite design: one write authority, a
+**When you join via this page's flow, that lower-level config is now handled
-managed onboarding flow, and automatic ongoing sync — closer to what most
+for you.** The master auto-assigns each spoke a unique `LDAP_SERVER_ID` at
-"add a second office" or "add a home-lab spoke" setups actually want. **Don't
+join time and derives every site's LDAP URL from its already-known HTTPS
-combine the two** — pick one per deployment.
+endpoint — `theta-suite`'s `bootstrap/site-ldap-register.js` applies it,
+re-checked on every `setup.sh` run since the peer list grows as spokes join.
+You don't hand-set `LDAP_SERVER_ID`/`LDAP_REPLICATION_HOSTS` for a cluster
+built this way. See [Geo-Location Scaling](replication.html#automatic-config-via-multi-site-join)
+for the mechanics, and its documented limitation: the *master's* own
+replication list only updates on ITS next `setup.sh` run, not live the
+instant a new spoke joins.
+
+Still want fully independent, always-writable sites with no master/spoke
+concept at all? `CFG_LDAP_MMR_MANUAL=true` opts out of the automatic path so
+you can hand-set `LDAP_SERVER_ID`/`LDAP_REPLICATION_HOSTS` directly, same as
+before this integration existed.
 
 ## See also
 

docs/sso/replication.md

@@ -23,33 +23,58 @@ In an N-Way Multi-Master setup, every site runs a fully active OpenLDAP server (
 
 ## Configuration
 
-To enable replication, you must pass two environment variables to the `sso-manager` container:
+The container's entrypoint reads two environment variables to configure this
+-- `LDAP_SERVER_ID` (a unique integer for this node) and
+`LDAP_REPLICATION_HOSTS` (a space-separated list of every **other** node's
+LDAP URL) -- and, when both are set, automatically loads the `syncprov`
+module, enables `mirrormode`, and generates the necessary `syncrepl` blocks
+in `/etc/openldap/slapd.conf`.
 
-1. `LDAP_SERVER_ID`: A unique integer for this node (e.g., `1`, `2`, `3`). This MUST be unique across the cluster.
+### Automatic config via Multi-Site join
-2. `LDAP_REPLICATION_HOSTS`: A space-separated list of the LDAP URLs of all **other** nodes in the cluster.
 
-### Example using `theta-env` / Docker Compose
+**If you're using [Multi-Site join](multi-site.html) (`CFG_MASTER_DIRECTORY_URL`/`spoke.env`),
+you don't set these by hand.** The master assigns each spoke a unique
+`LDAP_SERVER_ID` at join time (the same way it assigns a WireGuard mesh
+index) and derives `LDAP_REPLICATION_HOSTS` from every site's already-known
+HTTPS endpoint (`ldaps://<same-host>:636`) -- `theta-suite`'s `bootstrap/
+site-ldap-register.js` applies it and re-checks on every `setup.sh` run,
+since the peer list grows as new spokes join, restarting `sso-manager` only
+when the computed config actually changed.
 
-**Site 1 (`setup.env` or `docker-compose.yml`)**
+**Known limitation**: the *master's* own `LDAP_REPLICATION_HOSTS` only gets
+recomputed when its `setup.sh` is re-run — there's no live push telling an
+already-running master about a spoke that joined five minutes ago. Re-run
+`setup.sh` on the master after bringing up a new spoke (or after promoting
+one to master) to pick up the current peer list. A spoke's own config, by
+contrast, is re-checked and applied on every `setup.sh` run there, which is
+the common/recurring event.
+
+### Manual configuration
+
+Have a topology outside a `theta-suite`-managed cluster (fully independent,
+always-writable sites, no master/spoke concept)? Set
+`CFG_LDAP_MMR_MANUAL=true` to skip the automatic path entirely and set the
+two variables directly -- without this, the automatic step runs on every
+deployment (every fresh install starts as a master) and will overwrite them.
+
+**Site 1**
 ```env
 LDAP_SERVER_ID=1
 LDAP_REPLICATION_HOSTS="ldaps://sso.site2.com:636 ldaps://sso.site3.com:636"
 ```
 
-**Site 2 (`setup.env` or `docker-compose.yml`)**
+**Site 2**
 ```env
 LDAP_SERVER_ID=2
 LDAP_REPLICATION_HOSTS="ldaps://sso.site1.com:636 ldaps://sso.site3.com:636"
 ```
 
-**Site 3 (`setup.env` or `docker-compose.yml`)**
+**Site 3**
 ```env
 LDAP_SERVER_ID=3
 LDAP_REPLICATION_HOSTS="ldaps://sso.site1.com:636 ldaps://sso.site2.com:636"
 ```
 
-Once configured, the container's entrypoint will automatically load the `syncprov` module, enable `mirrormode`, and generate the necessary `syncrepl` blocks in `/etc/openldap/slapd.conf`.
-
 ## User Locations
 
 When creating or editing a user, you can specify their **Location (Site)**. This maps directly to the standard LDAP `l` (localityName) attribute, allowing you to track which physical site a user belongs to natively within the directory.