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/App.jsx

@@ -3,6 +3,7 @@ import { AuthProvider } from './contexts/AuthContext.jsx'
 import { SiteProvider } from './contexts/SiteContext.jsx'
 import MaintenanceGate from './components/MaintenanceGate.jsx'
 import RequireAuth from './components/RequireAuth.jsx'
+import RoleGate from './components/RoleGate.jsx'
 
 // Public
 import Portal from './routes/public/Portal.jsx'
@@ -31,6 +32,8 @@ import DiscordBotAdmin from './routes/admin/views/DiscordBotAdmin.jsx'
 import AuthProvidersAdmin from './routes/admin/views/AuthProvidersAdmin.jsx'
 import UsersAdmin from './routes/admin/views/UsersAdmin.jsx'
 import AccountAdmin from './routes/admin/views/AccountAdmin.jsx'
+import Moderation from './routes/admin/views/Moderation.jsx'
+import ModerationUser from './routes/admin/views/ModerationUser.jsx'
 
 export default function App() {
   return (
@@ -73,6 +76,17 @@ export default function App() {
             <Route path="wiki" element={<WikiAdmin />} />
             <Route path="hero" element={<HeroEditor />} />
             <Route path="settings" element={<SettingsAdmin />} />
+            <Route
+              path="moderation"
+              element={
+                <RoleGate roles={['admin', 'moderator']}>
+                  <Outlet />
+                </RoleGate>
+              }
+            >
+              <Route index element={<Moderation />} />
+              <Route path="user/:discordId" element={<ModerationUser />} />
+            </Route>
             <Route path="activity" element={<ActivityAdmin />} />
             <Route path="bot-activity" element={<BotActivityAdmin />} />
             <Route path="discord-bot" element={<DiscordBotAdmin />} />