Summary

• Refactors the Rangefinder class to use a timer and pin IRQ for non-blocking distance measurements
• Measurements are taken continuously in the background (60ms cycle), so distance() returns immediately with the most recent value
• Timeouts are detected without blocking, returning MAX_VALUE (65535) instead of raising exceptions

Test plan

• Verify distance() returns valid measurements for objects within 2cm-4m range
• Verify distance() returns MAX_VALUE when no object is in range
• Verify the first call to distance() blocks until an initial reading is available
• Verify subsequent calls return immediately without blocking
• Test that the timer-based approach does not interfere with other XRP subsystems