feat(platform): Add confirmation modal for email verification

- Create reusable ConfirmationModal component with variants (info, warning, danger, success)
- Replace browser confirm() dialogs with styled modal for email verification
- Update PlatformBusinesses and PlatformUsers to use the new modal
- Add translation keys for verification messages
- Unverify test@example.com for testing

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/src/i18n/locales/en.json

@@ -602,6 +602,8 @@
     "verifyEmail": "Verify Email",
     "verify": "Verify",
     "confirmVerifyEmail": "Are you sure you want to manually verify this user's email?",
+    "confirmVerifyEmailMessage": "Are you sure you want to manually verify this user's email address?",
+    "verifyEmailNote": "This will mark their email as verified and allow them to access all features that require email verification.",
     "noUsersFound": "No users found matching your filters.",
     "roles": {
       "superuser": "Superuser",