Add moderation dashboard, user history & notes (Phase 6a)

Surface the Discord bot's moderation data on the admin panel: a read-only
staff dashboard over the existing mod_actions log, per-user history, staff
notes, and a new moderator role. No bot changes.

Schema
- users.role ENUM gains 'moderator' (CREATE + idempotent ALTER for existing DBs)
- new server-owned mod_notes table (staff_only/admin_only visibility)

Server
- model/moderation: read mod_actions via the shared pool (documented read-only
  cross of the bot/server ownership boundary), correlate accounts through
  user_identities (provider='discord'), flag automated actions via
  staff_user_id === bot_config.application_id; pure reshaping helpers isolated
  in moderation.pure.js so they unit-test without opening a DB pool
- model/modNotes: list/add with role-gated admin_only visibility
- admin/moderation.controller + routes under /api/v1/admin/moderation/* gated by
  requireRole('admin','moderator'); admin_only note writes require admin
- allow assigning 'moderator' in the user create/update validators

Client
- /admin/moderation overview (window tiles, type-filterable recent feed, user
  lookup) and /user/:discordId history (tabs + notes with add-note)
- RoleGate; AdminLayout filters nav and confines moderators to their section
- moderator badge + action-type/auto badges

Deferred (see plan): 6b bot event capture (joins/leaves/filter/spam), 6c appeals
(needs public accounts), 6d /internal/mod-reverse bot reversal callback.

Verified: 116 server unit tests, client build, DB-backed model smoke, full
HTTP/RBAC e2e, and a browser click-through of the dashboard.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019rao86n5cXpwAyjdBFEshV

client/src/routes/admin/AdminLayout.jsx

@@ -4,11 +4,15 @@ import MoonDot from '../../components/MoonDot.jsx'
 import { useAuth } from '../../contexts/AuthContext.jsx'
 import { useSite } from '../../contexts/SiteContext.jsx'
 
+// `roles` (when present) restricts which roles see a nav item. Items without it
+// are shown to admin/editor as before. Moderators are further confined to just
+// their own section + account security (see the redirect effect below).
 const NAV = [
   { to: '/admin', label: 'Dashboard', end: true },
   { to: '/admin/posts', label: 'Posts' },
   { to: '/admin/wiki', label: 'Wiki' },
   { to: '/admin/hero', label: 'Hero Editor' },
+  { to: '/admin/moderation', label: 'Moderation', roles: ['admin', 'moderator'] },
   { to: '/admin/settings', label: 'Settings' },
   { to: '/admin/activity', label: 'Activity' },
   { to: '/admin/bot-activity', label: 'Bot Activity' },
@@ -23,6 +27,7 @@ const TITLES = {
   '/admin/posts': 'Posts',
   '/admin/wiki': 'Wiki Pages',
   '/admin/hero': 'Hero Editor',
+  '/admin/moderation': 'Moderation',
   '/admin/settings': 'Site Settings',
   '/admin/activity': 'Activity Log',
   '/admin/bot-activity': 'Bot Activity',
@@ -48,11 +53,31 @@ export default function AdminLayout() {
   const { mode } = useSite()
   const navigate = useNavigate()
   const location = useLocation()
-  const title = TITLES[location.pathname] || 'Admin'
+  const title =
+    TITLES[location.pathname] ||
+    (location.pathname.startsWith('/admin/moderation') ? 'Moderation' : 'Admin')
   // The hero canvas editor needs room — let it use the full content width.
   const wide = location.pathname === '/admin/hero'
   const modeDot = mode === 'live' ? 'var(--mode-live)' : 'var(--mode-maint)'
 
+  // Moderators only get the moderation section + their own account security.
+  const isModerator = user?.role === 'moderator'
+  const navItems = NAV.filter((n) => {
+    if (n.roles && !n.roles.includes(user?.role)) return false
+    if (isModerator) return n.to === '/admin/moderation' || n.to === '/admin/account'
+    return true
+  })
+
+  // Confine a moderator who deep-links (or is redirected to the index) to a page
+  // outside their remit — the API would 403 anyway, so send them to their home.
+  useEffect(() => {
+    if (!isModerator) return
+    const p = location.pathname
+    if (!p.startsWith('/admin/moderation') && p !== '/admin/account') {
+      navigate('/admin/moderation', { replace: true })
+    }
+  }, [isModerator, location.pathname, navigate])
+
   // Keep the admin out of search indexes (belt-and-suspenders with robots.txt).
   useEffect(() => {
     const meta = document.createElement('meta')
@@ -94,7 +119,7 @@ export default function AdminLayout() {
         </div>
 
         <nav style={{ flex: 1, padding: '14px 12px', display: 'flex', flexDirection: 'column', gap: 4 }}>
-          {NAV.map((n) => (
+          {navItems.map((n) => (
             <NavLink
               key={n.to}
               to={n.to}