When source_voltage_mv is not specified, the PPK2 should be configured
in ampere meter mode via use_ampere_meter() so measurements work
correctly without sourcing voltage.

Fix: set ampere meter mode when no source voltage provided

This update introduces a new capture state management system to track measurement samples, sample rate, and publication status. It includes functionality to publish captured data as a CSV file, enhancing data handling capabilities. The cleanup process now ensures that captures are published upon termination. Additionally, the measuring functions have been updated to utilize this new state management.

Add capture state management and CSV export for PPK2 measurements

…y include analog_csv_dir

This change updates the ppk2_publish_capture function to only add the analog_csv_dir to the payload if tmpdir is not None, improving the clarity and efficiency of the payload creation process.

Refactor payload construction in ppk2_publish_capture to conditionall…