fix: preserve multi-cause reconcile warnings and align slot blocking

Co-authored-by: genichin <4282227+genichin@users.noreply.github.com>

tests/application/test_sync.py

@@ -199,6 +199,22 @@ def test_sync_holding_qty_mismatch_updated():
     assert not ws_out.is_warned(str(slot.slot_id))
 
 
+def test_sync_clears_only_b_case_when_slot_has_multiple_warning_causes():
+    slot = _make_slot(SlotState.HOLDING, qty=5.0)
+    ws = InMemoryReconcileWarningStore()
+    slot_id = str(slot.slot_id)
+    ws.set_warned(slot_id, portfolio_id="pf-005930", case_code="B")
+    ws.set_warned(slot_id, portfolio_id="pf-005930", case_code="C")
+
+    result, _repo, ws_out = _setup(slot, {"005930": 10}, warn_store=ws)
+
+    assert result["warning_cleared"] is True
+    assert ws_out.is_warned(slot_id) is True
+    info = ws_out.get_warning_info(slot_id)
+    assert info is not None
+    assert info["case_codes"] == ["C"]
+
+
 # ---------------------------------------------------------------------------
 # AC-4: WAC seed from cost_basis_port when available
 # ---------------------------------------------------------------------------