Changes

• On-call summaries: human-readable schedule, escalation & policy overviews
  • PR: #2630
• feat(ai): Sentinel live Investigation panel on the incident page
  • PR: #2629
• feat(ai): Sentinel Phase 1 — autonomous incident investigation engine
  • PR: #2623
• feat(ai): Sentinel Phase 0 — action belt (mutating copilot tools)
  • PR: #2624
• feat(ai): Sentinel Phase 2 — alert investigation + confidence-gated quiet mode
  • PR: #2625
• feat(ai): Sentinel Phase 3 — auto-draft postmortem on incident resolve
  • PR: #2626
• feat(ai): Sentinel Phase 4 — recurrence memory ("I've seen this before")
  • PR: #2627
• feat(ai): Sentinel "watch it think" — live per-step investigation narration
  • PR: #2628
• feat(dashboard): sort metric chart node list by value & move filter below chart
  • PR: #2631
• Sentinel investigation settings toggles
  • PR: #2633
• feat(on-call): render schedule calendar in schedule timezone + 'View as' switcher
  • PR: #2634
• feat(on-call): timezone bubble + modal picker with explicit save
  • PR: #2638
• fix(on-call): size timezone modal to content (standard labeled field)
  • PR: #2639
• docs(roadmap): split Sentinel roadmap into vision + execution tracker, re-baseline against shipped code
  • PR: #2640