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/commands/warnings.command.js

@@ -0,0 +1,34 @@
+const { PermissionFlagsBits, ApplicationCommandOptionType, EmbedBuilder } = require('discord.js')
+
+const warnings = require('../../model/warnings')
+
+module.exports = {
+  data: {
+    name: 'warnings',
+    description: "List a member's active warnings.",
+    default_member_permissions: PermissionFlagsBits.ModerateMembers.toString(),
+    options: [
+      { name: 'user', description: 'Member to look up', type: ApplicationCommandOptionType.User, required: true },
+    ],
+  },
+  async execute(interaction) {
+    const user = interaction.options.getUser('user', true)
+    const rows = await warnings.listActive(interaction.guildId, user.id)
+
+    if (rows.length === 0) {
+      await interaction.reply({ content: `${user.tag} has no active warnings.`, ephemeral: true })
+      return
+    }
+
+    const embed = new EmbedBuilder()
+      .setColor(0xe0b070)
+      .setTitle(`Warnings — ${user.tag}`)
+      .setDescription(
+        rows
+          .map((w, i) => `**${i + 1}.** ${w.reason || '(no reason given)'} — by ${w.staff_tag || 'unknown'} on ${new Date(w.created_at).toLocaleDateString()}`)
+          .join('\n'),
+      )
+
+    await interaction.reply({ embeds: [embed], ephemeral: true })
+  },
+}