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/discord/modLog.js

@@ -0,0 +1,53 @@
+// Shared by every moderation command (ban/kick/mute/warn): writes the audit
+// row and posts the embed to the configured mod-log channel. Takes `client`
+// as a parameter (from interaction.client) rather than importing
+// discordManager directly, to avoid a require cycle (discordManager -> commands
+// -> modLog -> discordManager).
+const { EmbedBuilder } = require('discord.js')
+
+const db = require('../db')
+const guildConfig = require('../model/guildConfig')
+const createLogger = require('../utils/logger')
+
+const log = createLogger('modlog')
+
+const COLOR = { ban: 0xd98b84, kick: 0xe0b070, mute: 0xe0b070, warn: 0xe0b070 }
+
+async function record({ client, guildId, actionType, target, staffUser, reason, durationSeconds }) {
+  await db.query(
+    `INSERT INTO mod_actions (guild_id, action_type, target_user_id, target_tag, staff_user_id, staff_tag, reason, duration_seconds)
+     VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,
+    [guildId, actionType, target.id, target.tag || null, staffUser.id, staffUser.tag || null, reason || null, durationSeconds || null],
+  )
+
+  try {
+    const channelId = await guildConfig.getModLogChannelId(guildId)
+    if (!channelId) return
+    const channel = await client.channels.fetch(channelId)
+    if (!channel || !channel.isTextBased()) return
+
+    const embed = new EmbedBuilder()
+      .setColor(COLOR[actionType] || 0x9aa5b1)
+      .setTitle(actionType.toUpperCase())
+      .addFields(
+        { name: 'Target', value: `${target.tag || target.id} (${target.id})`, inline: true },
+        { name: 'Staff', value: `${staffUser.tag || staffUser.id} (${staffUser.id})`, inline: true },
+      )
+      .setTimestamp()
+    if (reason) embed.addFields({ name: 'Reason', value: reason })
+    if (durationSeconds) embed.addFields({ name: 'Duration', value: formatDuration(durationSeconds), inline: true })
+
+    await channel.send({ embeds: [embed] })
+  } catch (err) {
+    log.warn('failed to post mod-log embed', { message: err.message })
+  }
+}
+
+function formatDuration(seconds) {
+  if (seconds % 86400 === 0) return `${seconds / 86400}d`
+  if (seconds % 3600 === 0) return `${seconds / 3600}h`
+  if (seconds % 60 === 0) return `${seconds / 60}m`
+  return `${seconds}s`
+}
+
+module.exports = { record }