fix(t1000-e): fix extended uptime failures in GPS and sensor code

[NickDunklee]

• Fix millis() wraparound (49-day) in T1000SensorManager::loop() and MicroNMEALocationProvider::loop() by switching from absolute comparison (millis() > next_) to elapsed-time arithmetic ((uint32_t)(millis() - last_) >= interval) with uint32_t timestamps; previous pattern could stall GPS updates and time sync for up to ~24 days after wraparound
• Fix div-by-zero crash in get_heater_temperature() when ntc_volt == 0 (open circuit or bad ADC read); now returns 0.0f safely
• Fix out-of-bounds array access in get_heater_temperature(): loop exit at i == 0 caused ntc_res2[i-1] / ntc_temp2[i-1] at index -1; loop exhaustion at i == 136 caused ntc_res2[136] one-past-end read; clamped i to [1, 135] with early-exit returns for edge temperatures and guarded interpolation denominator against zero