add sheet music OCR CLI tool using Audiveris

Adds a Typer CLI (sheet-music-ocr) that converts scanned sheet music
(PDF, PNG, JPG, TIFF) to MusicXML via Audiveris, preserving lyrics and
text annotations. Includes Audiveris in the nix dev shell.

https://claude.ai/code/session_017GqUbuRDT58toRaxMtfRmf

pyproject.toml

@@ -27,6 +27,7 @@ dependencies = [
 [project.scripts]
 database = "python.database_cli:app"
 van-inventory = "python.van_inventory.main:serve"
+sheet-music-ocr = "python.sheet_music_ocr.main:app"
 
 [dependency-groups]
 dev = [