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
- 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
