fix(issue-50): a waiter whose own attempt is already running answers clear, not superseded

The registry wait judged its record by one rule: not this attempt's
pending record in this session -> superseded (redispatched, moved or
closed by someone else). That also caught the record's own `started`
landing before the prompt went out - the Issue #14 registry ack winning
over an unreachable broker, as test_issue30_stall_watch_stop acknowledges
at registration - and the wrapper left on exit 5 instead of its
broker_unavailable path (rc 3).

A record that is running under this attempt's token in this session is
this attempt's own progress: the waiter answers `clear` at once, writes
no admission and starts no hold. Another token, another session or a
terminal status stay `superseded` (review 55219be1 R1 unchanged).

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

tests/test_issue50_dispatch.py

@@ -422,6 +422,32 @@ def test_u3g_a_waiter_whose_attempt_changed_in_place_leaves_the_admission_to_the
             proc.communicate()
 
 
+def test_u3i_an_attempt_already_running_under_its_own_token_is_clear_not_superseded(tmp_path):
+    # the Issue #14 registry ack: the agent's `started` for this attempt lands
+    # before the prompt goes out (test_issue30_stall_watch_stop). Nothing to
+    # wait for, nothing foreign: `clear` at once, no admission written
+    a = _register(tmp_path, status="running")
+    _event(tmp_path, a, time.time())
+    me = _register(tmp_path)
+    tok = _rec(tmp_path, me)["dispatch_token"]
+    _edit(tmp_path, me, status="running")
+    before = _rec(tmp_path, me)
+    t0 = time.time()
+    assert decide.wait_open_jobs(_ns(tmp_path, me, wait_s=30)) == "clear"
+    assert time.time() - t0 < 5 and _rec(tmp_path, me) == before, "no wait, no write"
+    res = _cli(tmp_path, "wait-open-jobs", "--job", me, "--agent-session", "herdr:s", "--registry-dir", str(tmp_path),
+               "--wait-s", "30", "--timeout", "3600", "--dispatch-token", tok, "--hold")
+    assert res.stdout.strip() == "clear" and not _hold_pids(me), res.stderr
+    # running under another attempt's token, or in another session, is still someone else's
+    assert decide.wait_open_jobs(_ns(tmp_path, me, session="herdr:t")) == "superseded"
+    _edit(tmp_path, me, dispatch_token="another-attempt")
+    res = _cli(tmp_path, "wait-open-jobs", "--job", me, "--agent-session", "herdr:s", "--registry-dir", str(tmp_path),
+               "--wait-s", "30", "--timeout", "3600", "--dispatch-token", tok)
+    assert res.stdout.strip() == "superseded", res.stderr
+    _edit(tmp_path, me, dispatch_token=tok, status="completed")
+    assert decide.wait_open_jobs(_ns(tmp_path, me)) == "superseded"
+
+
 def test_u3h_the_pinned_token_is_the_wrappers_not_the_records(tmp_path):
     # the record's token changed before the waiter started (a redispatch raced
     # the wrapper): the waiter given the old token is superseded at once