feat(dashboard): track the UGC server like auth and chat

Online state with the time it came up, down/up alerts, a UGC column in the
health history, /api/servers (every server with its process memory and CPU)
and /api/servers/ugc, and UGC gauges for Prometheus.

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

dDatabase/GameDatabase/ITables/IServerHealth.h

@@ -16,6 +16,8 @@ public:
 		bool authOnline{};
 		bool chatOnline{};
 		uint64_t memoryKb{}; // all server processes together (Linux only, else 0)
+		bool ugcEnabled{};   // master starts the UGC server (in a bucket: at any sample)
+		bool ugcOnline{};    // in a bucket: at every sample
 	};
 
 	virtual void InsertHealthSample(const HealthSample& sample) = 0;