fix(issue-50): a claimed dry-run job holds its session (review 211037ab F1)

open_jobs skips a dry-run record only while it is pending: a pick-pending
claim makes it running work, which the admission must wait for.

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

tests/test_issue50_dispatch.py

@@ -174,8 +174,12 @@ def test_u1e_a_dry_run_record_is_not_an_open_job(tmp_path):
     me = _register(reg)
     assert decide.open_jobs(str(reg), "herdr:s", me) == ([], [])
     assert decide.wait_open_jobs(_ns(reg, me)) == "clear"
-    # control: the same record without the mark is an `injected` job that holds the session
-    _edit(reg, dry, dry_run=None)
+    # claimed by a pick-pending and started, it is running work (review 211037ab F1)
+    _edit(reg, dry, status="running")
+    _event(reg, dry, time.time(), event="started")
+    assert decide.wait_open_jobs(_ns(reg, me)) == f"busy {dry}"
+    # control: the pending record without the mark is an `injected` job that holds the session
+    _edit(reg, dry, status="pending", dry_run=None)
     assert decide.wait_open_jobs(_ns(reg, me)) == f"busy {dry}"