Rename to checkLinkPermissions and stop log following on revoke

The old name read as an unconditional unsubscribe. Log following has
its own subscription outside SubscriptionController, so check
core.log.follow on permission changes too. Move the per-connection
work into one helper and split the tests into userPermissionsUpdated
and rolesUpdated, checking the account update event is sent.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/controller/src/ControlConnection.ts

@@ -875,6 +875,16 @@ export default class ControlConnection extends BaseConnection {
 		this.updateLogSubscriptions();
 	}
 
+	/** Stop following logs if the user no longer has permission to */
+	checkLogPermission() {
+		try {
+			this.user.checkPermission("core.log.follow");
+		} catch {
+			this.logSubscriptions = { all: false, controller: false, hostIds: [], instanceIds: [] };
+			this.updateLogSubscriptions();
+		}
+	}
+
 	updateLogSubscriptions() {
 		let { all, controller, hostIds, instanceIds } = this.logSubscriptions;
 		if (all || controller || hostIds.length || instanceIds.length) {