Enhance API and UI for incident management and live updates

- Added a new endpoint `/api/agg/incidents` to provide a normalized snapshot of incidents for fleet triage, including severity and recommended actions.
- Implemented live event streaming via `/api/live/events` for real-time updates on fleet status and incidents, enhancing observability.
- Updated the Web UI to include dedicated sections for incidents and live updates, improving user navigation and access to critical information.
- Enhanced API documentation to reflect new endpoints and their functionalities, ensuring clarity for developers and users.

docs/OPERATIONS_BASELINE.md

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+# Operations Baseline (Telemt Panel)
+
+## Purpose
+
+This document defines the baseline operating model and target SLO metrics for the Telemt response panel.
+It is used to measure impact of live updates, incidents workflow, and observability improvements.
+
+## Current Baseline (Before Rollout)
+
+- Dashboard refresh mode: mostly manual (`Refresh` buttons on key pages).
+- Unified incident queue: not present.
+- Alert ownership and acknowledgement flow: not present.
+- MTTR tracking: not formalized in product UI.
+- MTTD tracking: not formalized in product UI.
+- Cross-page filtering consistency: partial, per-page controls only.
+
+## Baseline Risks
+
+- Slow detection when operators do not refresh at the right time.
+- High context switching cost between pages during incidents.
+- No single place to triage partial/degraded node states.
+- Weak evidence trail for post-incident analysis.
+
+## SLO Targets (Phase Goals)
+
+- MTTD reduction: at least 30% versus baseline.
+- MTTR reduction: at least 25% versus baseline.
+- Manual refresh share during incident windows: under 10%.
+- Incident cards with `owner + ack + runbook`: over 90%.
+
+## Measurement Inputs
+
+- Gateway API:
+  - `/api/agg/fleet-status`
+  - `/api/agg/summary`
+  - `/api/agg/incidents` (planned/implemented in this rollout)
+- Gateway metrics endpoint:
+  - `/metrics`
+- Frontend telemetry (local panel interaction metrics):
+  - refresh actions
+  - ack/resolve actions
+  - stale/live state durations
+
+## Rollout Validation Checklist
+
+- [ ] Baseline values captured before enabling auto-refresh.
+- [ ] Incident flow tested with simulated degraded upstream.
+- [ ] Alert noise review completed after first week.
+- [ ] MTTD/MTTR comparison published for phase review.