test(update): the first transition reaches the skill and the conversion (Issue #72, criterion 5)

A v4.11.0 workspace's .mam_deploy/update.sh installs the new version - the
skill present, no updater left - and the skill run after it converts the
registry. An update-backup in an unknown state now restarts the monitor it
stopped: nothing was changed.

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

tests/test_issue72_update.py

@@ -708,3 +708,40 @@ def test_an_entry_holding_the_admission_lock_is_waited_for_or_refuses(box, wait,
     assert needle in res.stderr, res.stderr
     assert not (box.ws / "INSTALLER-RAN").exists()
     assert not (box.mam / "update-in-progress").exists()
+
+
+# --- the first transition (decision 4, criterion 5) ------------------------------------
+
+def test_the_old_updater_installs_the_skill_which_then_converts_the_registry(tmp_path):
+    """A workspace installed by v4.11.0 still has .mam_deploy/update.sh. Run once,
+    it installs the new version - the skill, and no updater left behind - and
+    copies the registry unconverted; the skill run right after converts it."""
+    old_src = tmp_path / "v4.11.0"
+    old_src.mkdir()
+    arch = subprocess.run(["git", "-C", str(REPO_ROOT), "archive", "0e1e2e8"], capture_output=True)
+    if arch.returncode != 0:
+        pytest.skip("no git history to rebuild v4.11.0 from")
+    subprocess.run(["tar", "-x", "-C", str(old_src)], input=arch.stdout, check=True)
+    root = Path(os.path.realpath(tmp_path))
+    ws = root / "ws"
+    ws.mkdir()
+    (root / "bin").mkdir()
+    (root / "bin" / "herdr").write_text(FAKE_HERDR)
+    (root / "bin" / "herdr").chmod(0o755)
+    b = Box(root, ws)
+    res = subprocess.run(["bash", str(old_src / "deploy" / "install.sh"), str(ws)],
+                         env=dict(b.env, MAM_REPO_URL=str(old_src)), capture_output=True, text=True, timeout=600)
+    assert res.returncode == 0, res.stdout + res.stderr
+    assert (ws / ".mam_deploy" / "update.sh").exists()
+    write_rows(ws, [row("old-one", status="stopped", kill_command="x", start_command="y")])
+
+    res = subprocess.run(["bash", str(ws / ".mam_deploy" / "update.sh"), "--force"], cwd=str(ws), env=b.env,
+                         capture_output=True, text=True, timeout=600, stdin=subprocess.DEVNULL)
+    assert res.returncode == 0, res.stdout + res.stderr
+    assert (ws / UPDATE_REL).exists() and not (ws / ".mam_deploy" / "update.sh").exists()
+    assert "registry_format" not in yaml.safe_load((ws / ".mam" / "agent-sessions.yaml").read_text())
+
+    res = b.update()
+    assert res.returncode == 0, res.stdout + res.stderr
+    assert "registry-format: 1 -> 2, rows changed: 1" in res.stdout
+    assert yaml.safe_load((ws / ".mam" / "agent-sessions.yaml").read_text())["registry_format"] == 2