Restore optional shell handling in launcher tests

docs/roadmap/remediation.md

@@ -1,15 +1,15 @@
 # Release tooling review findings
 
-Status: R1 complete; R2 open. Review baseline:
+Status: R1 and R2 complete; no open findings. Review baseline:
 `124a9fa57fb3f815bedbafe2d4819f6aa265ee7d`, covering the implementation commits
-after `cb40f1d`. This record requests corrections; no implementation was changed
-during review.
+after `cb40f1d`. The findings below preserve the review evidence; completion
+markers record the subsequent corrections. No implementation was changed during
+the original review.
 
 The selected architecture is substantially present: three declarative profiles,
 one host-normalized registered-tool helper, separate publication and page-only
 delivery, retained credential-directory ignoring, and focused wiring tests.
-The following issues should be addressed before considering the refactor fully
-complete.
+Both issues identified by the review have been addressed.
 
 ## R1 — P2: Reject raw helper command names as legacy module selectors
 
@@ -52,6 +52,16 @@ it adds no new accepted-version restriction.
 
 ## R2 — P2: Restore the tests' optional POSIX-shell execution boundary
 
+**Completed.** Launcher execution tests now discover `sh`, invoke it explicitly
+with the script path, and skip when it is unavailable. Profile assertions remain
+independent of shell availability. A regression case removes the fixture
+script's executable permission to verify interpreter invocation; it failed
+before the correction and passes afterward. The focused scripts suite and shell
+syntax checks passed with Go 1.26.8 on the available POSIX host. Running the
+compiled test binary with an empty `PATH` confirmed that every launcher
+execution case skips while all three profile assertions pass. Native Windows
+execution was not tested and no new platform guarantee is introduced.
+
 **Location:** [scripts/release_test.go](../../scripts/release_test.go), especially
 `fixture.run` at line 63 and the launcher test setup.
 

scripts/release_test.go

@@ -60,12 +60,16 @@ esac
 
 func (f fixture) run(t *testing.T, script string, status int, args ...string) (string, string, int) {
 	t.Helper()
-	cmd := exec.Command(filepath.Join(f.root, "scripts", script), args...)
+	shell, err := exec.LookPath("sh")
+	if err != nil {
+		t.Skip("POSIX shell is unavailable")
+	}
+	cmd := exec.Command(shell, append([]string{filepath.Join(f.root, "scripts", script)}, args...)...)
 	cmd.Dir = f.outside
 	cmd.Env = append(os.Environ(), "PATH="+filepath.Dir(f.root)+string(os.PathListSeparator)+os.Getenv("PATH"), "CALLS="+f.log, fmt.Sprintf("TOOL_STATUS=%d", status), "CDPATH=/tmp", "GOOS=windows", "GOARCH=arm64", "GOWORK=auto", "GOTOOLCHAIN=auto", "GOFLAGS=-trimpath -mod=mod")
 	var stdout, stderr strings.Builder
 	cmd.Stdout, cmd.Stderr = &stdout, &stderr
-	err := cmd.Run()
+	err = cmd.Run()
 	if err == nil {
 		return stdout.String(), stderr.String(), 0
 	}
@@ -183,6 +187,17 @@ func TestStatusAndStreams(t *testing.T) {
 	}
 }
 
+func TestLauncherUsesShell(t *testing.T) {
+	f := newFixture(t)
+	if err := os.Chmod(filepath.Join(f.root, "scripts", "releasekit"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	_, _, status := f.run(t, "releasekit", 0, "version")
+	if status != 0 {
+		t.Fatal(status)
+	}
+}
+
 func TestInvalidForms(t *testing.T) {
 	for _, tc := range []struct {
 		script string