test(cli): assert 'code' in search --help output (Bug #7 regression pin)

Why: Step 2 의 doc-comment edit 가 향후 누군가 value list 를 재정렬
하거나 alias section 으로 분리할 때 silently 사라질 risk. clap 의
--help 렌더링 가 doc-comment 의 free-form text 라 grep-only smoke 가
유일한 검출 수단.

Change: 신규 test file (kebab-cli convention `cli_*` prefix 답습).
CARGO_BIN_EXE_kebab 으로 fresh binary 실행, stdout 의 `code` substring
assert. spec §4.4 의 acceptance row 1:1 mapping.

Refs: docs/superpowers/specs/2026-05-27-v0.20-sub1-bugfix2-spec.md §4.4
/ §5 (acceptance row 4).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/kebab-cli/tests/cli_help_smoke.rs

@@ -0,0 +1,17 @@
+// crates/kebab-cli/tests/cli_help_smoke.rs
+//
+// Regression pin — `kebab search --help` 의 `--media` value list 가
+// `code` 를 노출. Bug #7 (v0.20.0 bugfix round 2 spec §4.4).
+
+#[test]
+fn search_help_lists_code_in_media_values() {
+    let out = std::process::Command::new(env!("CARGO_BIN_EXE_kebab"))
+        .args(["search", "--help"])
+        .output()
+        .expect("kebab search --help");
+    let stdout = String::from_utf8_lossy(&out.stdout);
+    assert!(
+        stdout.contains("`code`"),
+        "search --help must list 'code' as accepted --media value; stdout = {stdout}"
+    );
+}