Add Utils.retime to mimic karaoke templates (Kara-Templater reference)

[CoffeeStraw]

Mimic Karaoke Templater retime Method

Reference: Kara-Templater retime implementation

Proposal

Implement a function Utils.retime in PyonFX to closely mimic the karaoke templating logic found in Kara-Templater.

Signature

@staticmethod
def retime(mode: str, line: Line, word_syl_or_char: Word | Syllable | Char | None = None, *, offset_start=0, offset_end=0)

Usage Example

Utils.retime("start2syl", l, syl, start_offset=0, end_offset=0)

• start2syl: Mode to retime.
• l: The line to apply the edits to.
• syl: The syllable to use as data source.
• start_offset and end_offset: Optional integer offsets for timing adjustment.

Motivation

This feature will allow users to more easily port karaoke templates from Kara-Templater to PyonFX, making script migration and compatibility smoother for advanced timing effects.