feat(frontend): add aria-controls and Escape focus management to NotificationDropdown

frontend/src/components/NotificationDropdown.test.tsx

@@ -87,4 +87,53 @@ describe('NotificationDropdown empty state', () => {
         expect(await screen.findByText('New stream #7 created')).toBeInTheDocument();
         expect(screen.queryByTestId('notifications-empty-state')).not.toBeInTheDocument();
     });
+
+    it('exposes accurate aria-expanded and aria-controls attributes on the bell trigger', async () => {
+        mockStream();
+        render(<NotificationDropdown publicKey={PUBLIC_KEY} />);
+
+        const bellButton = screen.getByRole('button', { name: /notifications/i });
+        expect(bellButton).toHaveAttribute('aria-expanded', 'false');
+        expect(bellButton).toHaveAttribute('aria-controls', 'notifications-dropdown-menu');
+
+        await userEvent.click(bellButton);
+        expect(bellButton).toHaveAttribute('aria-expanded', 'true');
+        expect(document.getElementById('notifications-dropdown-menu')).toBeInTheDocument();
+    });
+
+    it('closes the dropdown on Escape and returns keyboard focus to the bell trigger button', async () => {
+        mockStream();
+        render(<NotificationDropdown publicKey={PUBLIC_KEY} />);
+
+        const bellButton = screen.getByRole('button', { name: /notifications/i });
+        await userEvent.click(bellButton);
+        expect(screen.getByRole('dialog', { name: 'Notifications' })).toBeInTheDocument();
+
+        // Move focus away from the bell button to a button inside the dialog
+        const closeButton = screen.getByRole('button', { name: 'Close notifications' });
+        closeButton.focus();
+        expect(closeButton).toHaveFocus();
+
+        await userEvent.keyboard('{Escape}');
+        expect(screen.queryByRole('dialog', { name: 'Notifications' })).not.toBeInTheDocument();
+        expect(bellButton).toHaveAttribute('aria-expanded', 'false');
+        expect(bellButton).toHaveFocus();
+    });
+
+    it('announces unread notification count via an aria-live polite region', async () => {
+        mockStream({
+            events: [
+                {
+                    type: 'created',
+                    data: { streamId: 42 },
+                    timestamp: 1_700_000_000_000,
+                },
+            ],
+        });
+        const { container } = render(<NotificationDropdown publicKey={PUBLIC_KEY} />);
+
+        const liveRegion = container.querySelector('[aria-live="polite"]');
+        expect(liveRegion).not.toBeNull();
+        expect(await screen.findByText('1 new notifications')).toBeInTheDocument();
+    });
 });

frontend/src/components/NotificationDropdown.tsx

@@ -25,6 +25,7 @@ export const NotificationDropdown: React.FC<NotificationDropdownProps> = ({ publ
     const [notifications, setNotifications] = useState<NotificationItem[]>([]);
     const [unreadCount, setUnreadCount] = useState(0);
     const containerRef = useRef<HTMLDivElement>(null);
+    const triggerRef = useRef<HTMLButtonElement>(null);
 
     const { events: streamEvents, connected } = useStreamEvents({
         userPublicKeys: [publicKey],
@@ -122,6 +123,7 @@ export const NotificationDropdown: React.FC<NotificationDropdownProps> = ({ publ
         const handleKeyDown = (event: KeyboardEvent) => {
             if (event.key === "Escape") {
                 setIsOpen(false);
+                triggerRef.current?.focus();
                 return;
             }
 
@@ -178,9 +180,11 @@ export const NotificationDropdown: React.FC<NotificationDropdownProps> = ({ publ
     {unreadCount} new notifications
 </span>
             <button
+                ref={triggerRef}
                 onClick={handleDropdownOpen}
                 aria-label={`Notifications${unreadCount > 0 ? `, ${unreadCount} unread` : ""}`}
                 aria-expanded={isOpen}
+                aria-controls="notifications-dropdown-menu"
                 aria-haspopup="dialog"
                 className="relative p-2 text-slate-400 hover:text-accent transition-colors"
                 disabled={!connected}
@@ -207,6 +211,7 @@ export const NotificationDropdown: React.FC<NotificationDropdownProps> = ({ publ
 
             {isOpen && (
                 <div
+                    id="notifications-dropdown-menu"
                     role="dialog"
                     aria-label="Notifications"
                     className="absolute right-0 mt-2 w-80 bg-background/95 backdrop-blur-md border border-glass-border rounded-2xl shadow-2xl z-[100] overflow-hidden animate-in fade-in slide-in-from-top-2"
@@ -218,7 +223,10 @@ export const NotificationDropdown: React.FC<NotificationDropdownProps> = ({ publ
                             {!connected && <span className="text-xs text-red-400">Reconnecting...</span>}
 
                             <button
-                                onClick={() => setIsOpen(false)}
+                                onClick={() => {
+                                    setIsOpen(false);
+                                    triggerRef.current?.focus();
+                                }}
                                 aria-label="Close notifications"
                                 className="text-slate-400 hover:text-white"
                             >