Email: Add Admin Email Monitoring Dashboard

Summary

Implements "Admin Email Monitoring" an admin-only dashboard to monitor transactional email jobs, inspect queue health, filter recent jobs, and manually retry failed deliveries.

Admin Email Monitoring

• New admin route: /admin/email-jobs
• Linked from the Admin Dashboard (admin role only)
• Current queue state widgets: Pending, Sent, Failed, Retrying
• Filters (auto-submit): Status, Email Type, Date Range, Recipient search
• Queue health panel: sent/failed today, backlog, oldest pending, recent errors
• Email jobs table with recipient, type, status, created, retries, last error, and per-row retry action
• Bulk retry: “Retry failed” for jobs matching current filters
• Manual retry re-queues failed jobs via EmailQueueService::retryFailedJob()

Backend

• Admin/EmailJobsController — index, retryFailed, retryAllFailed
• EmailJobsTable — findFiltered(), getSummaryStats(), recipient/type helpers
• EmailQueueService — retryFailedJob() for admin-initiated retries
• Routes for retry actions under /admin/email-jobs

Test plan

• Log in as admin → Admin Dashboard shows Email Monitoring card
• Open /admin/email-jobs → page loads with queue stats, filters, queue health, and jobs table
• Log in as non-admin → /admin/email-jobs returns forbidden
• Filter by status, email type, date range, and recipient → results update correctly
• Failed job → Retry in Actions column re-queues the job
• Retry failed button re-queues all failed jobs matching current filters
• Queue health metrics reflect current job state