Extract and insert 97 images from reference PDF into songs

Extract images from the CL6 PDF using pdfimages, map them to songs
via page-to-CL number matching, and insert \songimage commands.
Add insert-images.py script for repeatable extraction.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

songs/how-many-roads-blowin-in-the-wind.tex

@@ -41,4 +41,6 @@ Yes, 'n how many times can a man turn his head, \\
 pretending he just doesn't see?
 \end{verse}
 
+\songimage{images/img-029.png}
+
 \end{song}