shrink root README into a landing page with a docs map and focused contributor guidance
add TV_POWER_RUNBOOK as the canonical TV power rollout and canary runbook
add CHANGELOG and move project history out of README-style docs
refactor src README into a developer-focused guide (architecture, runtime files, MQTT, debugging)
prune redundant older HDMI docs and keep a canonical HDMI_CEC_SETUP path
update copilot instructions to a high-signal policy format with strict anti-shadow-README design rules
align references across docs to current files, scripts, and TV power behavior
- fix race where periodic captures could overwrite pending event_start and event_stop metadata before simclient published
- keep latest.jpg and meta.json synchronized so triggered screenshots are not lost
- add stale pending trigger self-healing to recover from old or invalid metadata states
- improve non-interactive capture reliability with DISPLAY and XAUTHORITY fallbacks
- allow periodic idle captures in development mode so dashboard previews stay fresh without active events
- add deeper simclient screenshot diagnostics for trigger and metadata handling
- add regression test script for metadata preservation and trigger delivery
- add root-cause and fix documentation for the screenshot MQTT issue
- align and deduplicate README screenshot and troubleshooting sections; update release notes to March 2026
- fix scripts/start-dev.sh .env loading to ignore comments safely and remove export invalid identifier warnings
- persist client config from MQTT for display manager volume control
- apply effective VLC volume from event volume and client multiplier
- support live runtime volume updates for active video playback
- make latest screenshot handoff atomic to avoid broken latest.jpg races
- ignore broken screenshot pointers when selecting fallback images
- fix screenshot size logging and document server-side volume control
- add process health bridge and monitoring flow between display_manager and simclient
- publish health + warn/error log topics over MQTT
- standardize log/payload/screenshot timestamps to UTC (Z) to avoid DST drift
- improve video handling: python-vlc fullscreen enforcement and runtime PID reporting
- update README and copilot instructions with monitoring architecture and troubleshooting
- add Phase 3 monitoring implementation documentation
- update gitignore for new runtime/log artifacts
Switch to Paho v2 callbacks; add loop_start() and reconnect_delay_set() for auto-reconnect
Rework on_connect/on_disconnect to v2 signatures; handle session_present and reconnection flows
Gate heartbeats with client.is_connected() and add short retry on rc=4 (NO_CONN)
Re-send discovery after reconnect; ensure re-subscription to all topics
Add startup terminal message with ISO timestamp in simclient.py
Docs: update README and Copilot instructions with reconnection/heartbeat guidance and benign rc=4 notes
