Implement Live Ring Buffer

[XploitGost]

Summary

• add a thread-safe, per-category bounded Live Ring Buffer for recent redacted live analysis records
• integrate packet, flow, alert, and Expert summaries into the existing capture pipeline
• expose protected recent-query and metrics APIs with bounded limits and Ops health pressure
• add compact responsive Ops UI visibility, documentation, configuration, and regression coverage

Validation

• python -m pip check
• python -m unittest discover -s tests -v (303/303)
• npm run test:ui (43/43)
• npm run build
• PyInstaller packaged backend smoke
• production npm audit: 0 vulnerabilities
• desktop/mobile visual QA: no horizontal overflow

Scope

This PR only implements Live Ring Buffer Step 6. It does not add benchmark/soak tooling, service attribution, incident correlation, AI actions, command/control, remote shell, file collection, Agent raw forwarding, TLS decryption, MITM, credential collection, or IPS behavior.