- Fix datasource: bucket=smartcity, token=my-super-token, org=digitribe
- Fix dashboard queries: filter by topic tag instead of _measurement
(all data in measurement 'mqtt_consumer', type in tag 'topic')
- Fix field names: temperature_c→temperature_celsius, luminosity→brightness_lux
- Update dashboard to v3 with 15 panels (airquality, traffic, parking, weather, noise, light)
- Update TODO.md and session_resume
Tested: PM2.5 ✅, Temperature ✅, Vehicle Count ✅ via Grafana API
