fix(test): type drizzle mock callbacks for tsc

Co-authored-by: Cursor <[email protected]>

src/lib/services/staff-activity.test.ts

@@ -15,7 +15,8 @@ vi.mock("next/headers", () => ({
 	headers: () =>
 		new Promise((resolve) =>
 			resolve({
-				get: (key) => (key === "x-real-client-ip" ? "192.168.1.1" : null),
+				get: (key: string) =>
+					key === "x-real-client-ip" ? "192.168.1.1" : null,
 			}),
 		),
 }));