fix(issue-50): review findings of PR #56 on macOS

- admission: a `submit --dry-run` record is marked dry_run and is not an
  open job of its session (review 1e25cf2f F1)
- create: the monitor-row adoption requires the row's server to be the one
  this create spawned on (review 1e25cf2f F2)
- pane lock: retry only on contention (BlockingIOError); the docs say the
  flock lasts while any fd-9 holder (the claim shell and the shim) lives
  (review 66680d9d)
- tests on macOS: real-herdr box HOMEs under /tmp (sun_path is 104 bytes),
  resolved paths, the fake claude reads non-canonical input (MAX_CANON 1024)
  and the pane is read unwrapped; lock holders exec their sleep so killing
  them frees the lock; the adoption tests name the server

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

.agents/skills/lib_py/delegation/wrapper.py

@@ -297,6 +297,8 @@ def open_jobs(registry_dir: str, session: str, job_id: str, now: Optional[int] =
         rec = _load_record(registry_dir, other)
         if rec is None or _bare(str(rec.get("agent_session") or "")) != sess:
             continue
+        if rec.get("dry_run"):  # a submit --dry-run is never dispatched (review 1e25cf2f F1)
+            continue
         status = rec.get("status")
         if status == "running":
             idle = _int_field(rec, "idle_timeout_sec", DEFAULT_IDLE_TIMEOUT_SEC)