Add import-songs.py script that extracts songs from the PDF text
and generates .tex files with leadsheets format. Adds song
properties for all reference books (BuLiBu, BuLiBuII, CL, SwA,
Barde, LiBock). Generates all-songs.tex with alphabetical inputs.
Note: Chord alignment is approximate from PDF extraction and
may need manual review for some songs.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
