Add a request to mark hosts and the controller as needing a restart

Not every plugin arrives through PluginInstallRequest. Plugins checked
out into external_plugins or installed by hand on the machine never
flag a restart, so the web UI shows nothing and tooling that acts on
the flag never fires.

HostMarkRestartRequiredRequest and ControllerMarkRestartRequiredRequest
set config.restartRequired, guarded by the existing restart
permissions. They are exposed as "Mark Restart Required" in the control
dropdown of the host and controller pages, hidden once the flag is set,
and as mark-restart-required ctl commands. The mark shows up on the
next system metrics poll.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

packages/controller/src/ControlConnection.ts

@@ -73,6 +73,9 @@ export default class ControlConnection extends BaseConnection {
 
 		this.handle(lib.ControllerStopRequest, this.handleControllerStopRequest.bind(this));
 		this.handle(lib.ControllerRestartRequest, this.handleControllerRestartRequest.bind(this));
+		this.handle(
+			lib.ControllerMarkRestartRequiredRequest, this.handleControllerMarkRestartRequiredRequest.bind(this)
+		);
 		this.handle(lib.ControllerUpdateRequest, this.handleControllerUpdateRequest.bind(this));
 		this.handle(lib.ControllerConfigGetRequest, this.handleControllerConfigGetRequest.bind(this));
 		this.handle(lib.ControllerConfigSetRequest, this.handleControllerConfigSetRequest.bind(this));
@@ -1297,6 +1300,10 @@ export default class ControlConnection extends BaseConnection {
 		return usersToSend;
 	}
 
+	async handleControllerMarkRestartRequiredRequest() {
+		this._controller.config.restartRequired = true;
+	}
+
 	async handleControllerUpdateRequest(request: lib.ControllerUpdateRequest) {
 		if (!this._controller.config.get("controller.allow_remote_updates")) {
 			throw new lib.RequestError("Remote updates are disabled on this machine");