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>

bot/src/model/guildConfig.js

@@ -0,0 +1,47 @@
+// Per-guild key/value config the bot owns (see guild_config in
+// server/db/schema.sql). Generic get/set now; filters/schedules/role-menu
+// config reuses this same table in later phases.
+const db = require('../db')
+
+const MOD_LOG_CHANNEL_KEY = 'mod_log_channel_id'
+const AUTO_ROLE_KEY = 'auto_role_id'
+const INVITE_CHANNEL_KEY = 'invite_channel_id'
+const NEWS_CHANNEL_KEY = 'news_channel_id'
+
+async function get(guildId, key) {
+  const rows = await db.query('SELECT value FROM guild_config WHERE guild_id = ? AND `key` = ? LIMIT 1', [guildId, key])
+  return rows[0] ? rows[0].value : null
+}
+
+async function set(guildId, key, value) {
+  await db.query(
+    `INSERT INTO guild_config (guild_id, \`key\`, value) VALUES (?, ?, ?)
+     ON DUPLICATE KEY UPDATE value = VALUES(value)`,
+    [guildId, key, value],
+  )
+}
+
+const getModLogChannelId = (guildId) => get(guildId, MOD_LOG_CHANNEL_KEY)
+const setModLogChannelId = (guildId, channelId) => set(guildId, MOD_LOG_CHANNEL_KEY, channelId)
+
+const getAutoRoleId = (guildId) => get(guildId, AUTO_ROLE_KEY)
+const setAutoRoleId = (guildId, roleId) => set(guildId, AUTO_ROLE_KEY, roleId)
+
+const getInviteChannelId = (guildId) => get(guildId, INVITE_CHANNEL_KEY)
+const setInviteChannelId = (guildId, channelId) => set(guildId, INVITE_CHANNEL_KEY, channelId)
+
+const getNewsChannelId = (guildId) => get(guildId, NEWS_CHANNEL_KEY)
+const setNewsChannelId = (guildId, channelId) => set(guildId, NEWS_CHANNEL_KEY, channelId)
+
+module.exports = {
+  get,
+  set,
+  getModLogChannelId,
+  setModLogChannelId,
+  getAutoRoleId,
+  setAutoRoleId,
+  getInviteChannelId,
+  setInviteChannelId,
+  getNewsChannelId,
+  setNewsChannelId,
+}