swarm-controller: make authelia's operators matrix homeserver admins

swarm-authelia-bridge gains ListOperators, the usernames in authelia's
operator group (`operatorGroup = "admins"`, passed in from
swarm-authelia.nix). Unlike the two agent verbs, which admit any active
token, it answers only the client named by
SWARM_AUTHELIA_BRIDGE_OPERATOR_READER_CLIENT_ID (swarm-controller's
queueClientId) and returns 403 to every other active token: authelia
issues machine tokens to every hive and its agents as well. The bridge's
introspection now models `client_id` to make that check, the same way
swarm-nats-auth's does.

swarm-controller runs a grant-only pass at start and every five minutes:
read the group, map each username to the account an SSO login lands on
(tuwunel lowercases `preferred_username`), skip anyone already joined to
`#admins:<server>` (tuwunel's definition of admin) or without a matrix
account, and send `!admin users make-user-admin <user>` there as @swarm
with the swarm appservice token. Nothing is ever revoked: tuwunel has no
command for it (#4799).

The admin-room calls (alias, joined members, profile, send) go into
swarm-matrix-client next to whoami, keeping its no-body-in-errors rule.

Closes #4585

nix/host-modules/swarm-authelia.nix

@@ -924,6 +924,11 @@ in
               # includes `bridgeClient`) — same file this container's own
               # `renderClient` reads the digest half of.
               SWARM_AUTHELIA_BRIDGE_CLIENT_SECRET_FILE = "${clientsDir}/${bridgeClientId}.secret";
+              # The operator list names who holds operator rights, so the
+              # bridge answers it to the controller's client and refuses every
+              # other active token (each hive and its agents hold one).
+              SWARM_AUTHELIA_BRIDGE_OPERATOR_READER_CLIENT_ID = hyperhiveCfg.swarm.controller.queueClientId;
+              SWARM_AUTHELIA_BRIDGE_OPERATOR_GROUP = operatorGroup;
             };
           };