test: add unit tests for Uptime page and setup API

frontend/src/test/setup.spec.ts

@@ -0,0 +1,16 @@
+import { describe, it, expect } from 'vitest'
+
+describe('Test setup file checks', () => {
+  it('sets the React act environment flag', () => {
+    expect(globalThis.IS_REACT_ACT_ENVIRONMENT).toBe(true)
+  })
+
+  it('stubs window.matchMedia with expected interface', () => {
+    const mq = window.matchMedia('(min-width: 100px)')
+    expect(mq.matches).toBe(false)
+    expect(typeof mq.addListener).toBe('function')
+    expect(typeof mq.removeListener).toBe('function')
+    expect(typeof mq.addEventListener).toBe('function')
+    expect(typeof mq.removeEventListener).toBe('function')
+  })
+})