fix(coordination): stop phantom re-delegation from text-vs-id AC-ref mismatch (#259)

A parent's acceptance-criteria coverage is matched by stable criterion id, but
a PM may declare covers_parent_criteria on a child by EITHER the criterion's id
OR its full text (both happen in practice). _parent_ac_ref_sets unioned the raw
refs and matched by id only, so a COMPLETED child that declared coverage by text
was invisible to the matcher: the criterion read "uncovered", the roll-up gate
refused, and the PM re-delegated the already-finished work as a brand-new empty
subtask (0 commits, no PR) that can never close — looping for hours and burning
tokens (observed live: a parent's xenon work completed + merged via one child,
then re-delegated 2h later as an empty phantom).

Normalize every child ref to the criterion id (text -> id via the parent's own
criteria) in a small _normalize_ac_refs helper, so coverage counts regardless of
how it was declared. Fixes existing mismatched data and future declarations; all
three consumers (uncovered/unclaimed/parent_ac_coverage) share the builder. An
unknown ref (neither id nor a current criterion text) passes through and matches
nothing, exactly as before. Adds two regression tests.

Co-authored-by: Renn F <rennf93@users.noreply.github.com>

tests/unit/services/test_task.py

@@ -672,6 +672,46 @@ async def test_uncovered_parent_acs_empty_when_all_covered() -> None:
     assert await svc.uncovered_parent_acceptance_criteria(parent.id) == []
 
 
+@pytest.mark.asyncio
+async def test_uncovered_parent_acs_recognizes_text_declared_coverage() -> None:
+    # Regression (phantom re-delegation): a PM may declare covers_parent_criteria
+    # by the criterion's full TEXT instead of its id. Matching is by id, so a
+    # COMPLETED child that declared coverage by text used to read "uncovered" —
+    # and the PM re-delegated the already-finished work as an empty phantom
+    # subtask (0 commits, no PR) that could never close. _parent_ac_ref_sets now
+    # normalizes text -> id so coverage counts regardless of how it was declared.
+    parent = _build_task(
+        acceptance_criteria=["crit a", "crit b"],
+        acceptance_criteria_ids=["id-a", "id-b"],
+    )
+    svc = _svc_with_children(
+        parent,
+        [
+            (TaskStatus.COMPLETED, ["crit a"]),  # declared by TEXT, not "id-a"
+            (TaskStatus.COMPLETED, ["id-b"]),  # declared by id
+        ],
+    )
+    assert await svc.uncovered_parent_acceptance_criteria(parent.id) == []
+
+
+@pytest.mark.asyncio
+async def test_parent_ac_coverage_normalizes_text_refs() -> None:
+    # A text-declared coverage ref from a COMPLETED child surfaces as
+    # claimed+verified, same as an id-declared one.
+    parent = _build_task(
+        acceptance_criteria=["crit a", "crit b"],
+        acceptance_criteria_ids=["id-a", "id-b"],
+    )
+    svc = _svc_with_children(parent, [(TaskStatus.COMPLETED, ["crit a"])])
+    cov = await svc.parent_ac_coverage(parent.id)
+    assert cov[0] == {
+        "id": "id-a",
+        "text": "crit a",
+        "claimed": True,
+        "verified": True,
+    }
+
+
 @pytest.mark.asyncio
 async def test_parent_ac_coverage_maps_claimed_and_verified() -> None:
     # Per-criterion visibility: a COMPLETED child both claims and verifies its