fix(admin): address PR #623 second-pass review feedback

- Fix VALID_STATUSES fallback to use uppercase enum value
- Add TODO comment on InviteListItem cast pending type regeneration
- Guard revoke action against null id (returns fail 400)
- Add request: to delete action mock events for Sentry consistency
- Add expiresAt forwarding test for create action
- Add null-id guard test for revoke action

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/routes/admin/invites/page.server.spec.ts

@@ -203,6 +203,22 @@ describe('admin/invites create action', () => {
 
 		expect(result).toMatchObject({ status: 500, data: { createError: 'INTERNAL_ERROR' } });
 	});
+
+	it('includes expiresAt in POST body when provided', async () => {
+		const fd = new FormData();
+		fd.append('expiresAt', '2026-12-31');
+		mockFetch.mockResolvedValueOnce(mockResponse(true, successBody, 201));
+
+		await actions.create({
+			request: new Request('http://localhost', { method: 'POST', body: fd }),
+			fetch: mockFetch as unknown as typeof fetch
+			// eslint-disable-next-line @typescript-eslint/no-explicit-any
+		} as any);
+
+		const [req] = mockFetch.mock.calls[0] as [Request, unknown];
+		const sent = await req.json();
+		expect(sent.expiresAt).toBe('2026-12-31');
+	});
 });
 
 describe('admin/invites revoke action', () => {
@@ -254,4 +270,15 @@ describe('admin/invites revoke action', () => {
 
 		expect(result).toMatchObject({ status: 404, data: { revokeError: 'NOT_FOUND' } });
 	});
+
+	it('returns fail(400) when revoke id is missing', async () => {
+		const result = await actions.revoke({
+			request: new Request('http://localhost', { method: 'POST', body: new FormData() }),
+			fetch: mockFetch as unknown as typeof fetch
+			// eslint-disable-next-line @typescript-eslint/no-explicit-any
+		} as any);
+
+		expect(mockFetch).not.toHaveBeenCalled();
+		expect(result).toMatchObject({ status: 400 });
+	});
 });