`zig build test` now runs the full examples/ + issues/ regression corpus
alongside the Zig unit tests, driven by a pure-Zig test
(src/corpus_run.test.zig) — no shell script in the build path. It spawns
the installed `sx` per example (subprocess-isolated, per-run timeout),
diffs stdout/stderr/exit and optional `sx ir` snapshots, and fails the
build on any mismatch. The file list is enumerated at runtime, so new
examples are covered with no test edit.
- `sx ir` / `ir-dump` now write to stdout (fd 1) instead of stderr, so
the dumps can be piped/redirected.
- `zig build test -Dupdate-goldens` regenerates snapshots in-build,
byte-identical to the legacy `run_examples.sh --update`; on mismatch
the runner prints how to regenerate.
- run_examples.sh kept (still used by tools/verify-step.sh) and made
portable to a bare macOS: timeout/gtimeout fallback, bash 3.2-safe
empty-array handling.
- CLAUDE.md: document the new workflow.