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/mysql/36_character_snapshots.sql

@@ -0,0 +1,13 @@
+/* Earlier versions of characters' XML (zlib-compressed), taken before dashboard edits and daily for changed characters. */
+CREATE TABLE IF NOT EXISTS character_snapshots (
+    id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
+    character_id BIGINT NOT NULL,
+    taken_at BIGINT NOT NULL,
+    reason VARCHAR(100) NOT NULL DEFAULT '',
+    actor VARCHAR(64) NOT NULL DEFAULT '',
+    size INT UNSIGNED NOT NULL DEFAULT 0,
+    hash CHAR(64) NOT NULL DEFAULT '',
+    xml LONGBLOB NOT NULL,
+    INDEX character_snapshots_character (character_id, id),
+    INDEX character_snapshots_taken (taken_at)
+);