test: add beforeEach to reset theme state

Add beforeEach hook to ensure theme is reset to 'socket' before each
test runs, preventing test pollution from affecting "should default to
socket theme" test.

Fixes test failure where theme state leaked between tests.

Author: jdalton

test/themes.test.ts

@@ -13,10 +13,14 @@ import {
   withTheme,
   withThemeSync,
 } from '@socketsecurity/lib/themes'
-import { afterEach, describe, expect, it } from 'vitest'
+import { afterEach, beforeEach, describe, expect, it } from 'vitest'
 
 describe('themes', () => {
-  // Reset theme to default after each test to ensure isolation
+  // Reset theme to default before and after each test to ensure isolation
+  beforeEach(() => {
+    setTheme('socket')
+  })
+
   afterEach(() => {
     setTheme('socket')
   })