Fix board compatibility for XIAO RP2040 and other MicroPython platforms

[Copilot]

Users on XIAO RP2040 were encountering ImportError: no module named 'machine' because the codebase was written specifically for Pycom boards with non-standard I2C initialization syntax.

Changes

Library compatibility (lib/lidar.py)

• Added fallback imports for utime/time and relative/absolute constants
• Library core is now platform-agnostic

Board-specific examples

• example_rp2040.py - XIAO RP2040, Raspberry Pi Pico with pin mappings
• example_esp32.py - ESP32 with default GPIO21/22
• example_pycom.py - Original Pycom code preserved

Updated main.py

• Uses standard MicroPython I2C initialization instead of Pycom-specific syntax:

# Before (Pycom only)
i2c = I2C(0, mode=I2C.MASTER, baudrate=400000, pins=('P7', 'P8'))

# After (standard MicroPython)
i2c = I2C(0, scl=Pin(SCL_PIN), sda=Pin(SDA_PIN), freq=400000)

Documentation

• Added MicroPython firmware installation instructions
• Board-specific wiring diagrams and troubleshooting section
• Clear guidance on choosing the appropriate example file

Original prompt

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This section details on the original issue you should resolve

<issue_title>Issue regarding "import"</issue_title>
<issue_description>I am having an issue with a XIAO RP2040 I get an error which says ImportError: no module named 'machine', and if that is commented then another import error occurs. This is my first time working with this sensor and microcontroller and I will show screenshots of what I have. Thank you.

</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Issue regarding "import" #2

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