add UART sensor thread with passive/active modes and frame parser

[Sebenicz]

This PR introduces/updates the sensor module to support periodic particulate measurements over UART.
What changed:

• Added a dedicated sensor thread that:
• supports active reads for short periods and passive request/response + averaging for longer periods
• handles wake/sleep control and exposes a stop channel for graceful shutdown
• Added/updated a PMS frame parser with checksum validation and extraction of PM1.0/PM2.5/PM10 (ATM) readings