Add auto-detection of RP2040 BOOTSEL mass storage volumes (RPI-RP2) on
macOS, Linux, and Windows. Show detected volumes as upload targets with
a progress bar for UF2 file copy. Display helpful BOOTSEL instructions
when no RP2040 device is found.
- Add get_rp2040_mass_storage_volumes() to detect mounted RPI-RP2 volumes
- Add PortType.MASS_STORAGE and upload_using_uf2_copy() with progress bar
- Move ProgressBar to helpers.py for shared use
- Wait for USB-CDC serial port after upload for log output
- Auto-select single serial port for logs after mass storage upload
- Create firmware.bin.signed in post_build to fix nobuild upload target
- Show BOOTSEL tip when only OTA options are available