Add modern Ops Inbox to /ops

[mergemaven11]

Closes #213

Summary

• add a modern founder-facing Ops Inbox near the top of /ops
• normalize existing service health, grouped errors, 5xx failures, slow requests, and admin audit activity into message cards
• add priority levels, unread state, search, All / Needs attention / Updates / Snoozed / Archived filters
• add Mark read, Snooze 1h, Archive/Restore actions using browser-local state only
• add a Discuss recommended badge for higher-priority items
• preserve all existing detailed diagnostics below the inbox
• keep the message model integration-ready for GitHub, PostHog, HubSpot, Metricool, Stripe, Netlify, Render, and Atlas without exposing secrets or raw customer payloads

Safety

• no production infrastructure or billing changes
• no new backend write endpoints
• no secrets, tokens, request bodies, query strings, or raw integration payloads are displayed
• existing /ops authorization remains the gate

Validation

Run Frontend CI, Backend CI, Security CI, and any required checks on the exact PR head before merge.