feat(long-press): support secondary action on extended hold

Added optional secondary action for volume long press.

When enabled, holding the button longer triggers a second action
after the primary long-press action. This allows combining track
skipping with rewind/fast-forward.

Examples:
- long press → skip track
- extended hold → skip + fast forward

or

- long press → rewind
- extended hold → rewind + skip track

Also refactored volume key handler state management and event logic.

Author: Hepolise