fix(i18n): add missing actionUsers/Monitoring/Analytics dashboard keys

Quick Actions rendered raw i18n keys instead of translated labels for the
Users/Monitoring/Analytics actions. Also reverts useMockData back to its
pre-session value (false) after manual local verification.

Adds docs/KNOWN-ISSUES.md to track bugs found during manual QA, deferred
for a batch fix after the sprint.

src/app/i18n/en.ts

@@ -670,6 +670,9 @@ export const en: Translations = {
     actionTransactions: 'Transactions',
     actionOrders: 'Orders',
     actionMediaLibrary: 'Media Library',
+    actionUsers: 'Users & Permissions',
+    actionMonitoring: 'Monitoring',
+    actionAnalytics: 'Analytics',
     actionPreviewMarketplace: 'Preview Marketplace',
     activityTitle: 'Recent Activity',
     activityEmpty: 'No activity yet. Save or publish a change to see it here.',