Add runbook pack spec, validator, legacy launcher, and workplans RBT-WP-0002..0006

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Assistant: claude-code
Assistant-Model: sonnet
Assistant-Process: 295952@bnt-lap001
Assistant-Session: e93f64ad-516c-46eb-9666-aad8d300c477

tests/test_legacy.py

@@ -0,0 +1,46 @@
+import socket
+import sys
+import textwrap
+
+import pytest
+import yaml
+
+from rtut import legacy, pack as P
+
+
+def free_port():
+    s = socket.socket(); s.bind(("127.0.0.1", 0)); p = s.getsockname()[1]; s.close(); return p
+
+
+def make_repo(tmp_path, command, url, cwd="."):
+    d = tmp_path / "runbooks" / "old"
+    d.mkdir(parents=True)
+    (d / "pack.yaml").write_text(yaml.safe_dump({
+        "spec": "runbook-pack/v0.1", "id": "t.old", "title": "Old console", "owner": "t",
+        "exercise_status": "unexercised", "engine": "legacy-command",
+        "legacy": {"command": command, "cwd": cwd, "url": url}}))
+    return P.load(d / "pack.yaml")
+
+
+def test_launch_and_stop(tmp_path):
+    port = free_port()
+    pk = make_repo(tmp_path, [sys.executable, "-m", "http.server", str(port), "--bind", "127.0.0.1"],
+                   f"http://127.0.0.1:{port}")
+    proc = legacy.launch(pk, timeout=10)
+    try:
+        assert proc.poll() is None
+    finally:
+        proc.terminate(); proc.wait(5)
+
+
+def test_timeout_when_console_never_answers(tmp_path):
+    pk = make_repo(tmp_path, [sys.executable, "-c", "import time; time.sleep(30)"],
+                   f"http://127.0.0.1:{free_port()}")
+    with pytest.raises(TimeoutError):
+        legacy.launch(pk, timeout=1)
+
+
+def test_cwd_escape_refused(tmp_path):
+    pk = make_repo(tmp_path, ["true"], "", cwd="../..")
+    with pytest.raises(ValueError):
+        legacy.launch(pk)