ci: macOS lane runs test/gstack-launch-probe.test.ts under /bin/bash 3.2 (carries #3602's line, #3601)

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

.github/workflows/free-tests.yml

@@ -140,7 +140,8 @@ jobs:
   # code that compares a realpath with an unresolved path passes on Linux's
   # /tmp and fails here (#2982). TMPDIR is deliberately left at the runner's
   # default, and the job fails if that layout is not symlinked. It also sources
-  # the Codex probe from zsh, macOS's default shell (#3024; no paid call).
+  # the Codex probe from zsh, macOS's default shell (#3024; no paid call), and
+  # parses the launch probe with /bin/bash, which is bash 3.2 here (#3601).
   macos-named-regressions:
     runs-on: macos-latest
     timeout-minutes: 20
@@ -181,7 +182,7 @@ jobs:
           resolved="$(realpath "$tmp")"
           echo "temp root: $tmp -> $resolved"
           test "$resolved" != "${tmp%/}"
-          files=(test/gstack-design-detect.test.ts browse/test/chromium-profile-isolation.test.ts test/cso-git-hardening.test.ts test/plan-count-file-permission.test.ts test/spec-quality-gate-secret-sink.test.ts test/gstack-memory-ingest.test.ts test/regression-issue3024-zsh-sourced-helpers.test.ts test/codex-probe-subcommands.test.ts browse/test/proxy-env-daemon.test.ts browse/test/proxy-direct-launch-args.test.ts)
+          files=(test/gstack-design-detect.test.ts browse/test/chromium-profile-isolation.test.ts test/cso-git-hardening.test.ts test/plan-count-file-permission.test.ts test/spec-quality-gate-secret-sink.test.ts test/gstack-memory-ingest.test.ts test/regression-issue3024-zsh-sourced-helpers.test.ts test/gstack-launch-probe.test.ts test/codex-probe-subcommands.test.ts browse/test/proxy-env-daemon.test.ts browse/test/proxy-direct-launch-args.test.ts)
           for file in "${files[@]}"; do test -f "$file"; done
           bun test "${files[@]}"