A .ai in PostScript form went only to the PostScript interpreter, which
stopped on the first operator its missing prolog would define
(`Adobe_packedarray`, `Lb`, `Np`): files from Rhino and other CAD apps name
the procsets without including them.
- Such a program is its own editing data: when it has layers
(`%AI5_BeginLayer`) and no private data, the editing-data reader reads it,
compared with the page when the program runs, from the layers alone when
it can't be run. If the layers can't be read either, the error says why.
- The reader takes the legacy ten-operand `Lb`, ignores flatness `i`, and
uses the bounding box as the page when nothing else says where it is.
- Tests on synthetic files; fuzz fixture and hostile-program layers added.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
# Conflicts:
# ROADMAP.md
# docs/file-format-parity.md
# docs/gaps.md
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