test(fusion_accounting_bank_rec): integration tests for engine end-to-end flows

Tests engine behavior using factories (Task 18) instead of SQL fixtures.
Covers simple match, partial chain, multi-invoice batch, suggest-then-
accept flow, unreconcile reversal, and edge cases.

Two tests are intentionally failing — they expose real engine bugs
that should be fixed in a follow-up:

- TestReconcilePartialChain.test_partial_reconcile_leaves_residual:
  reconcile_one() builds counterpart vals using the full invoice
  residual, which leaves the bank move unbalanced when bank amount
  is smaller than the invoice (UserError: entry not balanced).
- TestUnreconcile.test_unreconcile_removes_partial: unreconcile()
  unlinks partial.reconcile rows but does not restore the suspense
  line on the bank move, so account.bank.statement.line.is_reconciled
  remains True after reversal.

Made-with: Cursor

fusion_accounting_bank_rec/tests/__init__.py

@@ -8,3 +8,4 @@ from . import test_confidence_scoring
 from . import test_reconcile_engine_unit
 from . import test_reconcile_engine_property
 from . import test_factories
+from . import test_reconcile_engine_integration