Refactor admin UI for consolidated navigation and improved moderation workflow

- Updated Sidebar component to consolidate navigation items under new categories: Moderation, Content, and Operations.
- Removed outdated pages and integrated their functionalities into tabs under Players, Activity, Content, and Settings.
- Introduced new Activity and Content pages to house Audit, Player Logs, Community Board, and Loading Tips with tabbed navigation.
- Created a unified Moderation page combining Players, Bans, and Reports with tabbed navigation.
- Refactored individual pages (e.g., Audit, Bans, CommunityBoard, etc.) to support embedded mode for better integration within modals.
- Added Tabs component for consistent tab navigation across multiple pages.
- Updated README to reflect changes in navigation and settings structure.
- Removed Grants page as it is not yet implemented.

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

@@ -0,0 +1,26 @@
+import { CommunityBoard } from './CommunityBoard';
+import { LoadingTips } from './LoadingTips';
+import { PageHeader } from '../components/PageHeader';
+import { Tabs, useTabParam } from '../components/Tabs';
+
+// The two player-facing content surfaces the watch pulls on dorm load —
+// the community board and the loading-screen tips — share one page.
+// Old /community and /loading-tips routes redirect here.
+export function Content() {
+  const [tab, setTab] = useTabParam<'community' | 'tips'>('community', ['community', 'tips']);
+  return (
+    <div>
+      <PageHeader title="Content" blurb="Player-facing content shown on dorm load: the community board and loading-screen tips." />
+      <Tabs
+        tabs={[
+          { key: 'community', label: 'Community board' },
+          { key: 'tips', label: 'Loading tips' },
+        ]}
+        active={tab}
+        onChange={setTab}
+      />
+      {tab === 'community' && <CommunityBoard embedded />}
+      {tab === 'tips' && <LoadingTips embedded />}
+    </div>
+  );
+}