## Problem PRD US-A6 is entirely missing. No data persistence for sensor history, no time-range graphs, no CSV export. ## Acceptance Criteria - [ ] Store last 24 hours of sensor data locally (SQLite or flat file) - [ ] View graphs for different time ranges (1h, 6h, 24h) - [ ] Export data to CSV ## Notes Low priority per PRD. Sparkline 60s buffer (#23) is the first step.
Problem
PRD US-A6 is entirely missing. No data persistence for sensor history, no time-range graphs, no CSV export.
Acceptance Criteria
Notes
Low priority per PRD. Sparkline 60s buffer (#23) is the first step.