Add Discord bot (moderation, filters, scheduling, roles, invites, site integration)

Standalone bot/ service (its own package.json/Dockerfile) managed entirely
through a new admin-only Discord Bot panel — token stored encrypted in the
DB and pushed to the bot process in-memory, never an env var. Built in
phases, each independently verified against a live Discord guild:

- Bot skeleton: gateway connection, internal shared-secret API, self-heals
  on its own restart by pulling config from the site
- Moderation core: /ban /kick /mute /warn /warnings + mod-log channel
- Word/invite/spam filtering with leetspeak-resistant normalization and a
  staff role/channel allowlist
- Scheduled messages: recurring (cron) and one-off channel posts
- Role assignment: button role menus, auto-role on join, temp roles,
  bulk role ops
- Auto-rotating primary invite with an audit log
- Site integration: news-publish -> Discord announce webhook, manual
  /announce, read-only /wiki search

Also fixes a pre-existing bug in both DB pools (server + bot): the mariadb
driver defaulted to timezone 'local', silently mis-serializing bound Date
params by the host's local offset instead of the DB's UTC session.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

server/src/utils/db.js

@@ -16,6 +16,13 @@ const pool = mariadb.createPool({
   insertIdAsNumber: true,
   bigIntAsNumber: true,
   decimalAsNumber: true,
+  // The driver defaults to 'local' — silently serializing bound JS Date
+  // params using the HOST MACHINE's local offset instead of the DB session's
+  // timezone (discovered via the Discord bot's temp_roles.expires_at coming
+  // back hours off in dev). 'auto' negotiates the actual session timezone so
+  // Date round-trips correctly regardless of host TZ — affects any write of
+  // a JS Date param, e.g. botConfig.model.js's last_connected_at.
+  timezone: 'auto',
 })
 
 /**