Fix matrix-rustpush-bridge ketesa managed-users regex namespace

The puppet localpart namespace was renamed from imessage_ to rustpush_
to avoid overlap with the mautrix-wsproxy iMessage bridge, but the
asManagedUsers regex still referenced the old imessage_ namespace.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

group_vars/matrix_servers

@@ -5082,7 +5082,7 @@ matrix_ketesa_config_asManagedUsers_auto: |
     +
     ([
       '^@'+(matrix_rustpush_bridge_appservice_bot_username | default('') | regex_escape)+':'+(matrix_domain | regex_escape)+'$',
-      '^@imessage_[a-zA-Z0-9_.+-]+:'+(matrix_domain | regex_escape)+'$',
+      '^@rustpush_[a-zA-Z0-9_.+-]+:'+(matrix_domain | regex_escape)+'$',
     ] if matrix_rustpush_bridge_enabled else [])
     +
     ([