Built-in 64's slot-0 operand is a symbol-table-1 type-6 message id, and every
one of them now has caption text: 2683 of 2683 call sites across the 28 stage
scripts, 1338 distinct names, no residue of any kind.
This only became reachable once build_caption_text was switched to the IXUD
field table (537 -> 8800 lines); before that most of these names had nothing
to resolve to.
Adds isl_dialogue.py plus a committed Stage 02 sample. Does not settle which
recording plays for a given line, multi-page captions, or the other five
languages.
f611e0b618