docs: surface the Directory doc — register in-app, link from UI and site

docs/directory.md existed but was orphaned: not in the /docs registry,
not linked anywhere. Now:

- registered as /docs/directory ("Directory & Inventory")
- help icon on the Directory page header links to it (same pattern as
  users/groups/profile pages)
- linked from the docs site index feature list
- extended with the shared slug conventions (site_<name>, host_<hostname>),
  the automatic registration story (theta-env stack seeding, ldap-client
  Linux host enrollment), and the admin + read-only API surface (the
  read-only graph routes live at /api/discovery, not /api/directory).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/directory.md

@@ -57,3 +57,41 @@ Resources carry a flexible `metadata` JSON object that can store essential conte
 ## Navigating the UI
 
 The Directory Management interface provides a **Tree View** toggle that visually nests your resources, making it easy to comprehend your network topography at a glance. You can also filter, search, and sort your entire infrastructure inventory. From the tree view, you can click the green `+` icon next to any resource to instantly add a child resource beneath it.
+
+## Slug conventions
+
+Slugs are the stable identifiers automation keys off, so the tooling around the SSO Manager follows a shared convention:
+
+- **Sites**: `site_<name>` — e.g. `site_local`, `site_us-east`
+- **Hosts**: `host_<hostname>` — e.g. `host_pve1`, `host_web01`
+- **Services/apps**: a plain slug or `app_<name>` — e.g. `sso-manager`, `app_emby`
+
+The auto-created LDAP groups derive from the slug (`<slug>_access` / `<slug>_admin`), so keep slugs stable once access groups are in use.
+
+## Automatic registration
+
+You don't have to build the graph by hand — the theta42 tooling registers itself:
+
+### The stack itself (theta-env)
+
+[theta-env](https://github.com/theta42/theta-env)'s `./setup.sh` seeds the directory on every run with the stack it deploys:
+
+- a **site** (name from `CFG_SITE_NAME` in `setup.env`, default `local` → slug `site_local`) marked as the current site
+- the **host** the stack runs on (`host_<hostname>`), with IP, MAC address, OS, and kernel collected from the machine
+- the **services** it composes — SSO Manager, Proxy (management UI), OpenLDAP Directory (the LDAPS endpoint Linux hosts and LDAP-native apps bind to), and OpenResty Edge (the 80/443 data plane) — each with its address, internal port, and git repo
+- the proxy's auto-registered **OAuth client**, linked under its service
+
+The seed is idempotent and non-destructive: a resource whose slug already exists is considered operator-owned — the seed only fills in metadata fields you haven't set, and never overwrites your values.
+
+### Linux hosts (ldap-client)
+
+The `ldap-client` join script enrolls a Debian/Ubuntu machine for LDAP login (SSSD/PAM), LDAP-backed `sudo`, and SSH keys from the directory — and, when given an SSO API token, registers the machine as a `host_<hostname>` resource with its IP, MAC, OS, and kernel, parented to the site named by its configured location.
+
+## API
+
+All of the above uses the same admin API the UI does (group `app_sso_directory_admin` or `app_sso_admin`):
+
+- `GET/POST /api/directory-admin/resources`, `PUT/DELETE /api/directory-admin/resources/:id`
+- `GET/POST/DELETE /api/directory-admin/edges` — parent/child links (`hosts`, `oauth` relations)
+- `GET/POST/DELETE /api/directory-admin/groups` — resource ↔ LDAP group links
+- Read-only graph views (any authenticated user): `GET /api/discovery/resources`, `/api/discovery/resources/:slug`, `/api/discovery/graph`, `/api/discovery/me`

docs/index.md

@@ -58,6 +58,7 @@ backend, that's the niche.
 - **All-in-one Docker image** — app + OpenLDAP + Redis in one container, or
   run the pieces separately via `app_*` env config.
 - **Geo-Location Scaling** — built-in support for N-Way Multi-Master OpenLDAP [replication](replication.html) across physical sites.
+- **[Directory & Inventory](directory.html)** — map sites, hosts, and services as a graph with rich metadata (IP/MAC, OS/kernel, ports, git repos), auto-provisioned access groups, and automatic registration from theta-env and ldap-client.
 
 ## Get it