test(issue-45): review - the real-server tests run on macOS, and the bootstrap config check follows the bootstrap's python3

claude round 1, B2 and B3 (B1 was the previous commit).

- B2, tests/test_issue45_restore.py: the throwaway root is resolved, because
  on macOS /tmp links to /private/tmp and herdr reports real paths (two B
  tests compared /tmp/... with /private/tmp/...). The server's environment
  is read from /proc on Linux and from `ps -E` elsewhere (macOS has no /proc;
  two A tests failed with FileNotFoundError).
- B3, tests/test_issue9_server_env.py: the bootstrap builds the config with
  the python3 on PATH, which here is 3.9 without tomllib, so the test's
  merged-settings expectation could not hold and its own `import tomllib`
  failed. The test now parses the result with that same python3; when it
  has no tomllib, it expects the key-only config and the bootstrap's
  "no tomllib" warning instead.

macOS, Python 3.9 venv: test_issue45_restore, test_issue9_server_env and
test_issue45_herdr_config 42 passed / 29 skipped (the tomllib-only checks).

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

tests/test_issue45_restore.py

@@ -157,10 +157,22 @@ class Rig:
         return self.argv_log.exists() and f"--resume {session_id}" in self.argv_log.read_text()
 
 
+def _process_env(pid: int) -> list:
+    """A process's environment as KEY=VALUE strings: /proc on Linux; on macOS
+    `ps -E` appends it to the command line, so the entries are matched there."""
+    proc = Path(f"/proc/{pid}/environ")
+    if proc.exists():
+        return [e.decode(errors="replace") for e in proc.read_bytes().split(b"\0") if e]
+    out = subprocess.run(["ps", "-E", "-ww", "-o", "command=", "-p", str(pid)],
+                         capture_output=True, text=True, timeout=10).stdout
+    return out.split()
+
+
 @pytest.fixture
 def rig(mam_sandbox, monkeypatch):
     # A pytest tmp_path is too long for a unix socket path under it.
-    root = Path(tempfile.mkdtemp(prefix="m45", dir="/tmp"))
+    # Resolved: on macOS /tmp is a link to /private/tmp and herdr reports real paths.
+    root = Path(tempfile.mkdtemp(prefix="m45", dir="/tmp")).resolve()
     session = f"mamt45-{os.getpid()}-{uuid.uuid4().hex[:4]}"
     for k in SCOPE_ENV:
         monkeypatch.delenv(k, raising=False)
@@ -224,8 +236,8 @@ def test_a_mam_server_does_not_relaunch_saved_agents(rig, user_session_table):
     info = rig.hd("pane", "process-info", "--pane", pane["pane_id"])["process_info"]
     assert info["foreground_process_group_id"] == info["shell_pid"], info
     # and it got there through HERDR_CONFIG_PATH
-    environ = Path(f"/proc/{rig.server_pids()[0]}/environ").read_bytes().split(b"\0")
-    assert f"HERDR_CONFIG_PATH={rig.user_cfg.parent / herdr_config.OUTPUT_NAME}".encode() in environ
+    want = f"HERDR_CONFIG_PATH={rig.user_cfg.parent / herdr_config.OUTPUT_NAME}"
+    assert want in _process_env(rig.server_pids()[0]), want
 
     # Positive control: the same saved layout under a plain server relaunches
     # the agent, so the "not resumed" above is not vacuous.