fix(lyrics): restore Kugou KRC sync with offset parsing, credit filtering, and whitespace token handling

[ajisth69]

Summary

Fixes word and line synchronization issues when playing Kugou lyrics.

Root Causes & Fixes

1. Global Offset Header Ignored:
   • Author [offset:X]\ headers in KRC payloads were skipped by line regex.
   • Now parsed with \krcOffsetRegex\ and applied to line and syllable timestamps.
2. Author/Song Credit Lines Filtered:
   • Introductory metadata (e.g. \Lyrics by:, \Composed by:, \Title - Artist) previously occupied 0–15s of playback with artificial or disordered timestamps.
   • Now filtered out via \isCreditLine\ and \creditLineRegex\ so playback and auto-scroll focus cleanly on actual sung vocals.
3. Whitespace Syllables Breaking Word Alignment:
   • Isolated whitespace syllable tokens (<...,...,0> ) caused \KaraokeLineSplitter.alignFragmentsToWords\ to abort on \strippedAtoms.any { it.isEmpty() }, collapsing into unmerged fragments.
   • Whitespace tokens now glue to previous syllables as trailing spaces rather than entering the syllable stream as empty words.
   • Also hardened \�lignFragmentsToWords\ to skip blank pieces defensively.
4. YouTube Track Title Search & Matching:
   • Strips leading \Artist - \ prefixes from title queries so YouTube video titles match Kugou candidate track names seamlessly.