APFS refuses names that are not valid UTF-8 (EILSEQ, os error 92), so the test's
create_dir_all(...).unwrap() panicked on macOS. The test now probes once with a
\xff folder; where that fails, the non-UTF-8 folder case and the non-UTF-8 entry
are skipped and the catalog-folder and symlink cases still run on a plain-named
folder. Where the probe succeeds (Linux, FreeBSD) the test is unchanged.
Run on macOS (case-insensitive APFS, rustc 1.99.0): the five tests in
tests_lightroom_folder pass, cargo fmt is clean, and clippy over lightcraft-engine
with --all-targets is clean. The ten sidecar tests of item 3 are not touched.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>