fix(kanban): accept created_cards linked as child of completing task

Widens _verify_created_cards to also accept ids that are children of the
completing task in task_links. Previously we only accepted cards where
created_by matched the completing task's assignee, which was too strict
for legitimate orchestrator flows: a specifier creates a card (so
created_by=specifier, not worker), then a worker picks it up and passes
parents=[current_task] to kanban_create. The explicit link proves the
relationship and should be trusted.

Salvaged from #20022 @LeonSGP43 (full PR superseded by #20232 +
this patch; the linked-children relaxation was the portable
improvement).

tests/hermes_cli/test_kanban_core_functionality.py

@@ -2978,6 +2978,46 @@ def test_complete_with_cross_worker_card_is_rejected(kanban_home):
         conn.close()
 
 
+def test_complete_accepts_cross_worker_card_when_linked_as_child(kanban_home):
+    """A card created by a different principal but explicitly linked as
+    a child of the completing task is accepted — the worker took
+    ownership via ``kanban_create(parents=[current_task])`` or an
+    explicit ``link_tasks`` call, which proves the relationship even
+    when ``created_by`` doesn't match.
+
+    (Relaxation salvaged from #20022 @LeonSGP43 — stricter version
+    would incorrectly reject legitimate orchestrator flows where a
+    specifier creates a card, then a worker picks it up and links it
+    to its own parent task.)
+    """
+    conn = kb.connect()
+    try:
+        parent = kb.create_task(conn, title="parent", assignee="alice")
+        # Card created by a DIFFERENT principal (not alice, not parent).
+        other = kb.create_task(
+            conn, title="other", assignee="x", created_by="bob",
+            parents=[parent],  # explicitly links as child of the completing task
+        )
+
+        ok = kb.complete_task(
+            conn, parent,
+            summary="completed with linked child",
+            created_cards=[other],
+        )
+        assert ok is True
+        # The card should appear in the completed event's verified_cards list.
+        import json as _json
+        row = conn.execute(
+            "SELECT payload FROM task_events "
+            "WHERE task_id=? AND kind='completed' ORDER BY id DESC LIMIT 1",
+            (parent,),
+        ).fetchone()
+        payload = _json.loads(row["payload"])
+        assert other in payload.get("verified_cards", [])
+    finally:
+        conn.close()
+
+
 def test_complete_prose_scan_flags_nonexistent_ids(kanban_home):
     """Successful completion whose summary references a ``t_<hex>`` id
     that doesn't resolve emits a ``suspected_hallucinated_references``