[bartekM-pl]

Add u-blox MAX-M10N (UBX, 20 Hz) support to the GNSS driver

Adds a UBX backend next to the existing NMEA/MTK (L76-L ) one. The receiver is detected automatically at start-up. GPS_init, GPS_getData and GPS_checkStatus are unchanged.

Changes

• GNSS_driver.c is now the common layer (UART, detection, parser task, queue). The old NMEA code moved to GNSS_nmea.c. New files: GNSS_ubx.c, ubx_parser.[ch] (pure C, no ESP-IDF dependency) and GNSS_types.h.
• Detection probes 115200 then 9600 baud with a UBX poll. A UBX reply means u-blox, NMEA text means L76-L, and no answer falls back to NMEA at 9600. A cold start takes about 1 s longer.
• u-blox setup: 115200 baud, UBX only, NAV-PVT at 20 Hz, GPS+Galileo only (needed for 20 Hz on the M10N), airborne <4g model, HDOP at 1 Hz. Settings go to RAM only, so detection reconfigures the receiver after each power cycle.
• gps_t grew: double lat/lon, MSL and ellipsoid altitude, full date, NED velocity, accuracy estimates, DOPs, itow_ms, rx_time_us and source.
• BOARD_cfg.h: parser task stack 2048 to 3072, UART ring buffer 1024 to 2048.

Behaviour changes

• NMEA altitude is now MSL. It used to be ellipsoid height, so NMEA readings are about 40 m lower in Poland.
• NMEA fixes: speed is now in m/s, the year includes 2000, and over-long fields no longer overflow.
• Removed nmea_parser_*, the unused event loop and the GSA/GSV arrays in gps_t. Nothing in the repo used them.

Testing

• Parser unit tests (host): 50 checks, run with make -C components/GNSS_driver/host_test run.
• Host simulation of the full init flow with fake u-blox and L76-L receivers: 20 Hz and 5 Hz delivered. The harness is not in this PR.
• ESP-IDF files were only syntax-checked against stubs. Not tested on hardware.

TODO

• Full build for the mega and mini targets.
• A MAX-M10N reaches 20 Hz (the driver logs "Solution rate" after 5 s).
• The L76-L receiver still gives 5 Hz.
• The NAV-DOP and constellation key IDs came from memory. A wrong key shows as a NAK warning in the log.

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