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>

migrations/dlu/sqlite/17_server_config.sql

@@ -0,0 +1,15 @@
+/* Server settings in the database, editable from the dashboard. See the MySQL migration. */
+CREATE TABLE IF NOT EXISTS server_config (
+    file TEXT NOT NULL,
+    name TEXT NOT NULL,
+    file_value TEXT NULL,
+    file_source TEXT NOT NULL DEFAULT '',
+    web_value TEXT NULL,
+    web_wins INTEGER NOT NULL DEFAULT 0,
+    secret INTEGER NOT NULL DEFAULT 0,
+    description TEXT NULL,
+    seen_at BIGINT NOT NULL DEFAULT 0,
+    updated_at BIGINT NOT NULL DEFAULT 0,
+    updated_by TEXT NOT NULL DEFAULT '',
+    PRIMARY KEY (file, name)
+);