Add option to pass through arguments to brwap, use shlex for dry-run

tests/integration.rs

@@ -245,6 +245,20 @@ fn dry_run_prints_and_exits() {
     );
 }
 
+#[test]
+fn dry_run_output_is_copy_pasteable_shell() {
+    let dry = sandbox(&["--dry-run"])
+        .args(["--", "bash", "-c", "echo $HOME"])
+        .output()
+        .expect("agent-sandbox binary failed to execute");
+
+    let dry_cmd = String::from_utf8_lossy(&dry.stdout).trim().to_string();
+    let args = shlex::split(&dry_cmd).expect("dry-run output is not valid shell");
+    assert_eq!(args[0], "bwrap");
+    assert_eq!(args[args.len() - 1], "echo $HOME");
+    assert_eq!(args[args.len() - 2], "-c");
+}
+
 #[test]
 fn blacklist_overlays_survive_tmp_bind() {
     fs::write("/tmp/ssh-sandbox-test", "secret").expect("failed to write sentinel");
@@ -649,6 +663,20 @@ fn mask_hides_file() {
     );
 }
 
+#[test]
+fn bwrap_arg_setenv_passes_through() {
+    let output = sandbox(&["--bwrap-arg", "--setenv MYVAR hello"])
+        .args(["--", "bash", "-c", "echo $MYVAR"])
+        .output()
+        .expect("agent-sandbox binary failed to execute");
+
+    let stdout = String::from_utf8_lossy(&output.stdout).trim().to_string();
+    assert_eq!(
+        stdout, "hello",
+        "expected --bwrap-arg to pass --setenv through to bwrap, got: {stdout}"
+    );
+}
+
 #[test]
 fn mask_nonexistent_path_becomes_tmpfs() {
     let dir = TempDir::new().unwrap();