Replace the onig C-dependency in expr with the pure-Rust fancy-regex crate.
This removes the onig_sys C library dependency while preserving full POSIX BRE,
backreference, multibyte UTF-8, and C locale compatibility.
expr depends on oniguruma, a C library, so cross-compiling it needs a
WASI sysroot: install wasi-sdk in the jobs that build wasm targets and
point CC/AR at it.
With that in place, neither expr nor test has to be excluded from the
wasmtime unit test run, and test_expr::/test_test:: can join the
integration tests run against the WASI binary.
Now that cspell runs locally via pre-commit, Style/spelling only annotates
unknown words rather than blocking the merge.
Also fix the pre_commit job, which ran "pre-commit run" without --all-files
and so matched zero files on a fresh checkout. Skip the hooks already covered
by the Style/format and Style/lint jobs, and drop the npm install of cspell
now that the hook provides its own.
Mirrors test_compare_test_results.py: covers human_kb formatting,
load_sizes (date-keyed and flat), compare() including threshold
boundaries on both growth and shrinkage, format_report, and an
end-to-end main() check that the comment file is only written when
something significant is reported.
Wired into code-quality.yml alongside the existing compare_test_results
unit tests.