feat: Refactor admin UI pages to support embedded mode and improve navigation

- Updated PlayerLogs, Players, Reports, Rooms, Settings, SignupCodes, and other pages to accept an optional `embedded` prop for better integration in various contexts.
- Introduced a new Activity page consolidating audit logs and player request logs with tab navigation.
- Added Content page for community board and loading tips with tab navigation.
- Created Moderation page to unify player directory, bans, and reports under a single interface.
- Implemented SettingsHome page to manage server settings and signup codes with tab navigation.
- Enhanced the Join page to include password creation for new accounts.
- Added global friends feature in Settings to allow all accounts to be friends without database entries.
- Introduced RelationshipQueries service to manage effective friend resolution based on global friends toggle.
- Added WireDates for consistent date handling in serialized data.
- Created reusable Tabs component for consistent tab navigation across various pages.

DorkNet.Server/admin-ui/src/pages/SettingsHome.tsx

@@ -0,0 +1,26 @@
+import { Settings } from './Settings';
+import { SignupCodes } from './SignupCodes';
+import { PageHeader } from '../components/PageHeader';
+import { Tabs, useTabParam } from '../components/Tabs';
+
+// Server-wide configuration: runtime toggles plus the single-use signup
+// invite codes (an access-control setting in its own right). Old
+// /signup-codes route redirects here with ?tab=signup.
+export function SettingsHome() {
+  const [tab, setTab] = useTabParam<'server' | 'signup'>('server', ['server', 'signup']);
+  return (
+    <div>
+      <PageHeader title="Settings" blurb="Runtime server toggles and single-use signup invite codes." />
+      <Tabs
+        tabs={[
+          { key: 'server', label: 'Server' },
+          { key: 'signup', label: 'Signup codes' },
+        ]}
+        active={tab}
+        onChange={setTab}
+      />
+      {tab === 'server' && <Settings embedded />}
+      {tab === 'signup' && <SignupCodes embedded />}
+    </div>
+  );
+}