- Add TimeSync fault code and labels in UI/SD/web docs
- Trigger receiver beacon bursts on sender drift, but keep errors sender-local
- Sender flags TimeSync only after TIME_SYNC_ERROR_TIMEOUT_MS
- Add BATTERY_CAL config and debug logging for raw ADC samples
- Use LiPo voltage curve (4.2V full, 2.9V empty) for % mapping
- Document battery calibration, curve, and debug output in README
- Track last OLED activity to avoid double timeout; keep power gating on transitions
- Copy TZ before setenv() in timegm_fallback to avoid invalid pointer reuse
- Add BATTERY_SAMPLE_INTERVAL_MS and only refresh cache at batch start when due
- Keep battery sampling to a single ADC read (Arduino core lacks explicit ADC power gating)
- Add LoRa idle/sleep/receive-window helpers and use short RX windows for ACK/time sync
- Schedule sender time-sync windows (fast/slow) and track RX vs sleep time in debug
- Lower sender power (80 MHz CPU, WiFi/BT off, reduced ADC sampling, unused pins pulldown)
- Make SERIAL_DEBUG_MODE a build flag, add prod envs with debug off, and document changes
- Add SD history chart + download listing to web UI
- Use HSPI for SD and fix SD pin mapping
- Swap role/OLED control pins and update role detection
- Update README pin mapping and SD/history docs
- Add optional microSD CSV logging per sender/day on receiver
- Wire logger into receiver packet handling
- Document new batch header fields, build envs, and SD logging
- Make sender links open in a new tab
