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/translations.ts

@@ -668,6 +668,9 @@ export interface Translations {
     actionTransactions: string;
     actionOrders: string;
     actionMediaLibrary: string;
+    actionUsers: string;
+    actionMonitoring: string;
+    actionAnalytics: string;
     actionPreviewMarketplace: string;
     activityTitle: string;
     activityEmpty: string;