[thisiskeithb]

Description

Three RP2040 fixes:

• LOW and HIGH are PinStatus enumerators on this core rather than macros, so the preprocessor evaluates both to 0 and every *_ENDSTOP_HIT_STATE check in SanityCheck.h fails regardless of the config. That breaks sensorless homing, BLTouch, and probe builds. The defines have to sit in Conditionals_type.h because it's included after HAL.h, once the enum exists.
• HAL.h forward-declares libServo without including Servo.h, so PAUSE_SERVO_OUTPUT() and RESUME_SERVO_OUTPUT() hit an incomplete type from neopixel.h and eeprom_flash.cpp. A servo on its own builds fine, which is why config-01 never caught it.
• flashFirmware() rebooted through the watchdog, so M997 restarted Marlin instead of entering the bootloader.

config-02.ini covers the first two.

Requirements

An RP2040 board. M997 needs one that exposes USB, like the SKR Pico.

Benefits

• Sensorless homing, BLTouch, and probe configs build on RP2040.
• Servos build alongside NeoPixels and flash EEPROM emulation.
• M997 reboots into the UF2 bootloader instead of back into Marlin.
• CI covers all three.

Configurations

Default configuration with MOTHERBOARD BOARD_BTT_SKR_PICO. buildroot/tests/SKR_Pico/config-02.ini has the exact options.

Related Issues

None.