docs: direct LDAP binds are first-class, not "legacy"

Linux hosts are a primary consumer of the directory — PAM/SSSD login,
LDAP-backed sudo rules (sudoRole), and SSH public keys (openssh-lpk) —
which is exactly what the custom schemas exist for. Describe LDAPS /
StartTLS consumers as "Linux hosts and LDAP-native apps" instead of
"legacy apps" across README, DEPLOYMENT, docs, and the Dockerfile.

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

docs/index.md

@@ -52,8 +52,9 @@ backend, that's the niche.
 - **Web management UI** — users, groups, and OAuth clients from a browser;
   invite and password-reset flows over email; self-service profile + API
   tokens.
-- **LDAPS for legacy apps** — anything that binds LDAP directly (Gitea,
-  Emby, …) uses LDAPS/StartTLS against the same directory.
+- **Direct LDAP binds** — anything that binds LDAP directly (Linux hosts
+  via PAM/SSSD, Gitea, Emby, …) uses LDAPS/StartTLS against the same
+  directory.
 - **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.