fix(issue-50): the loop path waits by the registry on its pending record (review F1-F3)

F1: from phase two on, the loop's `_registry_wait` ran before the record was
reset to pending, so the waiter held a terminal record: the engine refused its
dispatch_wait_at merge and other waiters never saw it in the FIFO. The wait
(and the idle wait after it) now follows the `--status pending` update; s1
pins the order and u3c shows why a terminal self record cannot signal.
F2: the real-herdr box teardown survives a hung stop/delete, kills a server
bootstrapped by a late client call, and asserts the server and HOME are gone.
F3: the delegate-job SKILL.md exit 5 row names the registry wait.
Also drops the dead loop in s1.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tests/test_issue50_dispatch.py

@@ -185,6 +185,21 @@ def test_u3_the_waiter_signals_on_its_own_record(tmp_path):
     assert me in {j for _c, j, _s in live}
 
 
+def test_u3c_a_terminal_self_record_cannot_carry_the_signal(tmp_path):
+    # why the loop path resets its record to pending before it waits (s1):
+    # the engine refuses a merge into a terminal record, so the waiter would
+    # stay invisible to every other waiter's FIFO
+    a = _register(tmp_path, status="running")
+    _event(tmp_path, a, time.time())
+    me = _register(tmp_path, status="completed")
+    assert decide.wait_open_jobs(_ns(tmp_path, me, wait_s=1)) == f"busy {a}"
+    after = json.loads((tmp_path / f"{me}.json").read_text())
+    assert after["status"] == "completed" and "dispatch_wait_at" not in after
+    later = _register(tmp_path)
+    live, _stale = decide.open_jobs(str(tmp_path), "herdr:s", later)
+    assert me not in {j for _c, j, _s in live}
+
+
 def test_u3b_the_signal_is_a_registry_merge(tmp_path, monkeypatch):
     me = _register(tmp_path)
     seen = {}
@@ -262,12 +277,14 @@ def test_s1_both_dispatch_paths_wait_by_the_registry_before_the_idle_wait():
     src = WRAPPER.read_text()
     assert src.count('_registry_wait "$JOB_ID" "$AGENT_SESSION"') == 1
     assert src.count('_registry_wait "$JOB_ID" "$current_session"') == 1
-    for block in src.split("wait_for_agent_idle ")[1:]:
-        pass
     direct = src.index('_registry_wait "$JOB_ID" "$AGENT_SESSION"')
     assert direct < src.index('wait_for_agent_idle "$AGENT_SESSION"')
     loop = src.index('_registry_wait "$JOB_ID" "$current_session"')
     assert loop < src.index('wait_for_agent_idle "$current_session"')
+    # the loop path waits on the record already reset to pending for this
+    # phase (review F1): a terminal self record cannot carry the signal (u3c)
+    assert src.count('--status "pending"') == 1
+    assert src.index('--status "pending"') < loop
     body = src.split("_registry_wait() {")[1].split("\n}\n")[0]
     assert "wait-open-jobs" in body and 'finalize_unfinished "$job_id" "error" "$SUB_RC_ERROR" "registry_wait"' in body
     assert "exit 5" in body and "mam_int_knob MAM_DISPATCH_WAIT_S 600 0" in body