Scope sandbox orphan probe to its own script (U5)

Why: The host-wide s.sh grep counted unrelated host scripts as sandbox escapes and failed the fixed combination even when its sandbox script had exited.

Evidence: SELF unrelated sentinel produced the exact original RED, while the scoped probe stayed GREEN under the same sentinel and detected its own positive-control script; full Backend Go tests passed. Receipts: /tmp/dependency-sandbox-host-collision-{red,green}-20261014-01a1345f.json and /tmp/dependency-backend-test-repair-all-go-green-20261014-01a1345f.json.

Impact: Test process identity check only; the sandbox process isolation implementation and failure condition for its own script are unchanged.

Refs: Backend PR #196; Dev PR #537; R8/R14

internal/tools/exec_backend_test.go

@@ -13,6 +13,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"strings"
+	"syscall"
 	"testing"
 	"time"
 )
@@ -87,6 +88,11 @@ func requireBwrap(t *testing.T) {
 
 // sandboxRun 经 sandbox 后端执行一段 bash 脚本，返回合并输出与退出描述。
 func sandboxRun(t *testing.T, script string, timeout time.Duration) (string, string) {
+	out, state, _ := sandboxRunWithPath(t, script, timeout)
+	return out, state
+}
+
+func sandboxRunWithPath(t *testing.T, script string, timeout time.Duration) (string, string, string) {
 	t.Helper()
 	dir := t.TempDir()
 	p := filepath.Join(dir, "s.sh")
@@ -117,7 +123,7 @@ func sandboxRun(t *testing.T, script string, timeout time.Duration) (string, str
 	if ctx.Err() == context.DeadlineExceeded {
 		state = "exit=timeout"
 	}
-	return out, state
+	return out, state, p
 }
 
 func TestSandboxHomeHidden(t *testing.T) {
@@ -207,17 +213,84 @@ func TestSandboxForkBombContained(t *testing.T) {
 
 func TestSandboxOrphansDieWithNamespace(t *testing.T) {
 	requireBwrap(t)
-	out, state := sandboxRun(t, ":(){ :|:& };:; echo gone", 30*time.Second)
+	out, state, scriptPath := sandboxRunWithPath(t, ":(){ :|:& };:; echo gone", 30*time.Second)
 	if state != "exit=0" || !strings.Contains(out, "gone") {
 		t.Fatalf("state=%s out=%q", state, out)
 	}
 	time.Sleep(500 * time.Millisecond) // 给孤儿进程留存活窗口
-	hb, err := exec.Command("bash", "-c", "ps -eo args | grep -c '[s]\\.sh' || true").Output()
+	count, err := sandboxScriptProcessCount(scriptPath)
 	if err != nil {
 		t.Skipf("host ps probe failed: %v", err)
 	}
-	if strings.TrimSpace(string(hb)) != "0" {
-		t.Fatalf("orphaned bomb survived outside the namespace: %s", hb)
+	if count != 0 {
+		t.Fatalf("sandbox script still has %d host processes: %s", count, scriptPath)
+	}
+}
+
+func sandboxScriptProcessCount(scriptPath string) (int, error) {
+	out, err := exec.Command("ps", "-eo", "args").Output()
+	if err != nil {
+		return 0, err
+	}
+	count := 0
+	for _, args := range strings.Split(string(out), "\n") {
+		if strings.Contains(args, scriptPath) {
+			count++
+		}
+	}
+	return count, nil
+}
+
+func TestSandboxOrphanProbeScopesScript(t *testing.T) {
+	dir := t.TempDir()
+	actual := filepath.Join(dir, "actual", "s.sh")
+	unrelated := filepath.Join(dir, "unrelated", "s.sh")
+	for _, path := range []string{actual, unrelated} {
+		if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(path, []byte("sleep 10 & wait\n"), 0o600); err != nil {
+			t.Fatal(err)
+		}
+	}
+	start := func(path string) {
+		proc := exec.Command("bash", path)
+		proc.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+		if err := proc.Start(); err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(func() { _ = syscall.Kill(-proc.Process.Pid, syscall.SIGKILL); _ = proc.Wait() })
+	}
+	start(unrelated)
+	for deadline := time.Now().Add(time.Second); ; {
+		count, err := sandboxScriptProcessCount(unrelated)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if count > 0 {
+			break
+		}
+		if time.Now().After(deadline) {
+			t.Fatal("unrelated control script did not start")
+		}
+		time.Sleep(time.Millisecond)
+	}
+	if count, err := sandboxScriptProcessCount(actual); err != nil || count != 0 {
+		t.Fatalf("unrelated process counted as this sandbox script: count=%d err=%v", count, err)
+	}
+	start(actual)
+	for deadline := time.Now().Add(time.Second); ; {
+		count, err := sandboxScriptProcessCount(actual)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if count > 0 {
+			break
+		}
+		if time.Now().After(deadline) {
+			t.Fatal("own sandbox script was not detected")
+		}
+		time.Sleep(time.Millisecond)
 	}
 }