- Add BQ27220 fuel gauge: reads SOC percentage every 5s
- Add BQ25896 PMIC: detects charging status (pre-charge/fast/done)
- Add MAX31329 external RTC: reads time on boot, syncs from NTP
- Battery UI: icon + percentage in header, cyan when charging
- Fix SD used bytes: fallback to recursive dir walk when usedBytes() returns 0
- Libraries: PMIC_BQ25896, kode_bq27220, kode_MAX31329
- Fix FTP using FFAT instead of SD_MMC: define both NETWORK_TYPE (6) and
STORAGE_TYPE (10) with numeric values to bypass FtpServerKey.h guard
- Fix SD capacity showing 'f/f GB': use integer math instead of floats
(LVGL builtin sprintf lacks %f support)
- Fix time/date labels tilting 45°: set fixed width + LV_TEXT_ALIGN_CENTER
- Switch LVGL sprintf to C stdlib for future float compatibility