feat: fleet ops, KEV scan, tunnels, beacon fallback, persistence

Extend owned-fleet control with scheduled tasks, audit log, file browser,
HTTPS beacon when WS drops, protocol tunnels, registry/autostart forge
options, KEV exposure in full sys check with Telegram alerts, and UI/tests.

agent/client/camera_stub.go

@@ -0,0 +1,12 @@
+//go:build !windows && !linux
+
+package client
+
+func handleCameraAction(action string) (handled bool, success bool, message string) {
+	switch action {
+	case "camera_snapshot", "camera_list":
+		return true, false, "camera capture is not supported on this platform"
+	default:
+		return false, false, ""
+	}
+}