fix: timer error accumulation not being reduced after compensation

[lazyze]

The accumulated_error_ns was being used to compensate timing jitter, but its value was never reduced, causing long-term overcompensation.

[CLAassistant]

All committers have signed the CLA.

[MambaWong]

never reduced? You can try to shorten the execution time or increase the interval time. Then see how it goes.