No project uses floating-point, so coprocessor_enable() was dead code.
Removes rp2350_coprocessor.c/.h and all references from reset handlers
and Makefiles across all 15 CBM drivers (0x01-0x0f).
- Single-wire protocol on GPIO4 via SIO register bit-bang
- TIMER0 TIMERAWL for microsecond pulse-width measurement
- Tick generator configured for 1 us ticks at 12 MHz clk_ref
- UART output: humidity/temperature or wiring failure message
- Zero warnings, 1876 bytes text