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- Removed outdated pages and integrated their functionalities into tabs under Players, Activity, Content, and Settings.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/components/Tabs.tsx

@@ -0,0 +1,50 @@
+import { useSearchParams } from 'react-router-dom';
+
+// Shared horizontal tab strip — the same underlined-button style the
+// per-player modal and the old Bans page already used inline, pulled
+// out so the consolidated hub pages (Players / Activity / Content /
+// Settings) all render their sub-tabs identically.
+export function Tabs<T extends string>({
+  tabs,
+  active,
+  onChange,
+}: {
+  tabs: ReadonlyArray<{ key: T; label: string }>;
+  active: T;
+  onChange: (key: T) => void;
+}) {
+  return (
+    <div className="flex border-b border-ink-800 text-sm mb-4 overflow-x-auto">
+      {tabs.map(t => (
+        <button
+          key={t.key}
+          onClick={() => onChange(t.key)}
+          className={`px-4 py-2 -mb-px border-b-2 whitespace-nowrap ${
+            active === t.key
+              ? 'border-brand-500 text-ink-50'
+              : 'border-transparent text-ink-300 hover:text-ink-100'
+          }`}
+        >
+          {t.label}
+        </button>
+      ))}
+    </div>
+  );
+}
+
+// Binds the active hub tab to a `?tab=` query param so the back-compat
+// redirects (e.g. /bans → /players?tab=bans) land on the right sub-tab
+// and the choice survives a refresh / shared link. The default tab
+// drops the param entirely to keep URLs clean.
+export function useTabParam<T extends string>(def: T, valid: readonly T[]): [T, (t: T) => void] {
+  const [params, setParams] = useSearchParams();
+  const raw = params.get('tab');
+  const active = (valid as readonly string[]).includes(raw ?? '') ? (raw as T) : def;
+  const set = (t: T) => {
+    const next = new URLSearchParams(params);
+    if (t === def) next.delete('tab');
+    else next.set('tab', t);
+    setParams(next, { replace: true });
+  };
+  return [active, set];
+}