Problem: ExtendScript's preprocessor directives weren't understood, so a
script (or ScriptUI panel, or library such as DuAEF) failed to parse at
its first `#include`; `#target` / `#targetengine` / `#strict` lines broke
parsing too.
Fix: before a script runs, `include::expand` inlines `#include "f"` and
`//@include "f"` in place of the line, resolved against the including
file's folder, then the folders of the latest `#includepath "a;b"`.
Each file is inlined once (which also breaks cycles), nesting is limited
to 32, files are capped at 16 MiB (64 MiB in all), and reads follow the
scripts' file gate (the script's own folder, the project's folder, or
anywhere with Allow Scripts to Write Files). `#target`, `#targetengine`,
`#strict`, `#script` and `#engine` are dropped. Errors in the expanded
code are mapped back to the included file and its line. Scripts without
directives run unchanged. File resolution, the gate and the limits live
in `scriptfile.rs` for `$.evalFile` (#760) to share.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>