feat: Created AdminDropdown component with click-outside/Escape close,…

- "frontend/src/components/AdminDropdown.tsx"
- "frontend/src/App.tsx"
- "frontend/src/App.css"

GSD-Task: S01/T01

frontend/src/App.css

@@ -776,6 +776,53 @@ body {
   color: var(--color-text-on-header-hover);
 }
 
+/* ── Admin dropdown ───────────────────────────────────────────────────────── */
+
+.admin-dropdown {
+  position: relative;
+}
+
+.admin-dropdown__trigger {
+  font-family: inherit;
+  font-size: 0.875rem;
+  color: var(--color-text-on-header);
+  background: none;
+  border: none;
+  cursor: pointer;
+  padding: 0;
+  transition: color 0.15s;
+}
+
+.admin-dropdown__trigger:hover {
+  color: var(--color-text-on-header-hover);
+}
+
+.admin-dropdown__menu {
+  position: absolute;
+  top: calc(100% + 0.5rem);
+  right: 0;
+  min-width: 10rem;
+  background: var(--color-bg-surface);
+  border: 1px solid var(--color-border);
+  border-radius: 0.5rem;
+  box-shadow: 0 4px 16px var(--color-shadow-heavy);
+  z-index: 100;
+  padding: 0.375rem 0;
+}
+
+.admin-dropdown__item {
+  display: block;
+  padding: 0.5rem 1rem;
+  color: var(--color-text-primary);
+  text-decoration: none;
+  font-size: 0.875rem;
+  transition: background 0.12s;
+}
+
+.admin-dropdown__item:hover {
+  background: var(--color-bg-surface-hover);
+}
+
 /* ── Home / Hero ──────────────────────────────────────────────────────────── */
 
 .home-hero {

frontend/src/App.tsx

@@ -9,7 +9,7 @@ import ReviewQueue from "./pages/ReviewQueue";
 import MomentDetail from "./pages/MomentDetail";
 import AdminReports from "./pages/AdminReports";
 import AdminPipeline from "./pages/AdminPipeline";
-import ModeToggle from "./components/ModeToggle";
+import AdminDropdown from "./components/AdminDropdown";
 
 export default function App() {
   return (
@@ -23,11 +23,8 @@ export default function App() {
             <Link to="/">Home</Link>
             <Link to="/topics">Topics</Link>
             <Link to="/creators">Creators</Link>
-            <Link to="/admin/review">Review</Link>
-            <Link to="/admin/reports">Reports</Link>
-            <Link to="/admin/pipeline">Pipeline</Link>
+            <AdminDropdown />
           </nav>
-          <ModeToggle />
         </div>
       </header>
 

frontend/src/components/AdminDropdown.tsx

@@ -0,0 +1,73 @@
+import { useEffect, useRef, useState } from "react";
+import { Link } from "react-router-dom";
+
+export default function AdminDropdown() {
+  const [open, setOpen] = useState(false);
+  const dropdownRef = useRef<HTMLDivElement>(null);
+
+  // Close on outside click
+  useEffect(() => {
+    function handler(e: MouseEvent) {
+      if (
+        dropdownRef.current &&
+        !dropdownRef.current.contains(e.target as Node)
+      ) {
+        setOpen(false);
+      }
+    }
+    document.addEventListener("mousedown", handler);
+    return () => document.removeEventListener("mousedown", handler);
+  }, []);
+
+  // Close on Escape
+  useEffect(() => {
+    function handler(e: KeyboardEvent) {
+      if (e.key === "Escape") setOpen(false);
+    }
+    if (open) {
+      document.addEventListener("keydown", handler);
+      return () => document.removeEventListener("keydown", handler);
+    }
+  }, [open]);
+
+  return (
+    <div className="admin-dropdown" ref={dropdownRef}>
+      <button
+        className="admin-dropdown__trigger"
+        onClick={() => setOpen((prev) => !prev)}
+        aria-expanded={open}
+        aria-haspopup="true"
+      >
+        Admin ▾
+      </button>
+      {open && (
+        <div className="admin-dropdown__menu" role="menu">
+          <Link
+            to="/admin/review"
+            className="admin-dropdown__item"
+            role="menuitem"
+            onClick={() => setOpen(false)}
+          >
+            Review
+          </Link>
+          <Link
+            to="/admin/reports"
+            className="admin-dropdown__item"
+            role="menuitem"
+            onClick={() => setOpen(false)}
+          >
+            Reports
+          </Link>
+          <Link
+            to="/admin/pipeline"
+            className="admin-dropdown__item"
+            role="menuitem"
+            onClick={() => setOpen(false)}
+          >
+            Pipeline
+          </Link>
+        </div>
+      )}
+    </div>
+  );
+}