fix(issue-45): review round 2 - an unrunnable config check is not a pass, odd pids never close a pane, nan does not drop settings

codex round 2 (PR #48).

- R1: when `herdr config check` could not run (timeout, OSError), the
  merged config was handed to the server as checked. A merge with a schema
  error makes herdr drop the whole file, restore back on - the #45 failure.
  The merged body is no longer used unchecked: _write_checked falls to the
  fixed MINIMAL config with a warning. When the check cannot run on MINIMAL
  either, MINIMAL is still used (with its own warning) rather than no
  config: returning none would leave restore on, and MINIMAL is a fixed
  two-line file the real-herdr test accepts. Unknown non-zero exits stay as
  they were - herdr exits non-zero for harmless warnings (an unknown
  section) that do not drop the file.
- R2: _shell_in_foreground compared shell_pid and the foreground group with
  ==, so 0/0, False/False, ""/"" or -1/-1 closed the pane. Both must now be
  positive ints (bool excluded) before they are compared.
- R3: the re-parse check used ==, and nan != nan, so a valid TOML nan threw
  away every other user setting even on Python 3.11. _same_doc compares
  documents recursively with nan equal to nan.

Tests: R1 (timeout, OSError) and R3 (top-level, array, nested nan) in
test_issue45_herdr_config.py; R2 in the new tests/test_issue45_restore_unit.py
(a herdr stub: zero, false, empty, negative, null, string, true, float;
missing info; a real shell closed; a busy pane kept). On the previous code
12 of them fail. Python 3.11: 67 passed; Python 3.9: 33 passed / 34 skipped
(tomllib-only). Real-herdr restore tests and related files on 3.9: 197
passed / 1 skipped.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VCgu9Fa9iT7TbJUSzdq4Ff

tests/test_issue45_restore_unit.py

@@ -0,0 +1,56 @@
+"""Issue #45 (B), review round 2 R2: resume closes a restored pane only when
+herdr's answer proves the shell is in the foreground. Odd pid values - missing,
+null, 0, negative, bool, string - must leave the pane alone. herdr is a stub
+here; the real-server behaviour is tests/test_issue45_restore.py."""
+from __future__ import annotations
+
+import sys
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent / ".agents" / "skills"))
+from lib_py import herdr_restore as hr  # noqa: E402
+
+SID = "probe-id"
+
+
+def _stub(monkeypatch, process_info):
+    calls = []
+
+    def fake(herdr, session, *args):
+        calls.append(args)
+        if args[:2] == ("pane", "list"):
+            return {"panes": [{"pane_id": "probe-pane", "agent": None, "agent_session": {"value": SID}}]}
+        if args[:2] == ("pane", "process-info"):
+            return {"process_info": process_info}
+        return {}
+    monkeypatch.setattr(hr, "_herdr", fake)
+    return calls
+
+
+@pytest.mark.parametrize("shell,fg", [(0, 0), (False, False), ("", ""), (-1, -1), (None, None),
+                                      ("123", "123"), (True, True), (1.0, 1.0)],
+                         ids=["zero", "false", "empty", "negative", "null", "string", "true", "float"])
+def test_an_odd_pid_answer_leaves_the_pane_alone(monkeypatch, shell, fg):
+    calls = _stub(monkeypatch, {"shell_pid": shell, "foreground_process_group_id": fg})
+    assert hr.close_restored_shells(SID, session="m45-review-probe") == []
+    assert ("pane", "close", "probe-pane") not in calls
+
+
+def test_a_missing_process_info_leaves_the_pane_alone(monkeypatch):
+    calls = _stub(monkeypatch, {})
+    assert hr.close_restored_shells(SID, session="m45-review-probe") == []
+    assert ("pane", "close", "probe-pane") not in calls
+
+
+def test_a_real_shell_in_the_foreground_is_closed(monkeypatch):
+    calls = _stub(monkeypatch, {"shell_pid": 4242, "foreground_process_group_id": 4242})
+    assert hr.close_restored_shells(SID, session="m45-review-probe") == ["probe-pane"]
+    assert ("pane", "close", "probe-pane") in calls
+
+
+def test_a_busy_pane_is_left_alone(monkeypatch):
+    calls = _stub(monkeypatch, {"shell_pid": 4242, "foreground_process_group_id": 4300})
+    assert hr.close_restored_shells(SID, session="m45-review-probe") == []
+    assert ("pane", "close", "probe-pane") not in calls