🔒 refactor(bots): remove !login command and enforce OIDC-only auth

- Remove !login and !logout commands from all 16+ Matrix bots
- Remove login/logout references from all help/welcome messages
- Disable password login in Synapse (password_config.enabled: false)
- System is now OIDC-only via Mana Core authentication

Users must authenticate via "Sign in with Mana Core" in Element.
Existing bot access tokens remain valid.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docker/matrix/homeserver.yaml

@@ -74,10 +74,10 @@ url_preview_ip_range_blacklist:
 enable_registration: false
 enable_registration_without_verification: false
 
-# Password config
+# Password config (disabled - all users authenticate via OIDC/SSO)
 password_config:
-  enabled: true
-  localdb_enabled: true
+  enabled: false
+  localdb_enabled: false
   pepper: "${SYNAPSE_PASSWORD_PEPPER:-change-me-pepper}"
 
 # Session lifetime (must be >= refresh_token_lifetime)