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/model/botConfig/botConfig.db.js

@@ -0,0 +1,28 @@
+const { query } = require('../../utils/db')
+
+const COLS =
+  'id, guild_id, bot_token_enc, application_id, enabled, status, status_detail, last_connected_at, updated_by, created_at, updated_at'
+
+// Singleton row (id = 1). Returns null until the admin saves it for the first time.
+async function get() {
+  const rows = await query(`SELECT ${COLS} FROM bot_config WHERE id = 1 LIMIT 1`)
+  return rows[0] || null
+}
+
+// Upsert the singleton row. `fields` are column values already prepared by the
+// model (token pre-encrypted). Only the provided columns are written/updated.
+async function upsert(fields) {
+  const cols = Object.keys(fields)
+  const vals = cols.map((c) => fields[c])
+  const insertCols = ['id', ...cols].map((c) => `\`${c}\``).join(', ')
+  const placeholders = ['1', ...cols.map(() => '?')].join(', ')
+  const updates = cols.map((c) => `\`${c}\` = VALUES(\`${c}\`)`).join(', ')
+  await query(
+    `INSERT INTO bot_config (${insertCols}) VALUES (${placeholders})
+     ON DUPLICATE KEY UPDATE ${updates}`,
+    vals,
+  )
+  return get()
+}
+
+module.exports = { get, upsert }