feat: web dashboard and playground work

The NexusDashboard-parity dashboard (dDashboardServer) and everything built on it on the experimental branch:
accounts, characters, properties and moderation tools, permissions shared with in-game slash commands, economy
reports, World 3D and property 3D views with client scenery, scheduled events (features, vanity changes, live
events, announcements, restarts), vanity files and events, the CDClient browser, the message inspector with saved
captures, chat filter tools, community challenges, live ops, the AI moderator helper, and the server-side changes
they need.

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

dDashboardServer/routes/PrometheusMetrics.h

@@ -0,0 +1,14 @@
+#pragma once
+
+/**
+ * Prometheus metrics at /metrics (and /api/metrics for API tokens): players and world instances, whether auth, chat and
+ * master are up, memory per server, chat, today's economy, moderation queues, strikes and scheduled task results.
+ *
+ * Off until metrics_enabled is set. A scraper then sends either an API token of an account with metrics_view, or the
+ * shared metrics_token, as Authorization: Bearer; metrics_allowed_ips can limit where requests come from. The text is
+ * built at most once every metrics_cache_seconds however often it is fetched, so scrapes never add up to heavy queries.
+ * The exposition format itself is in MetricsFormat.h.
+ */
+namespace PrometheusMetrics {
+	void RegisterRoutes();
+}