refactor(fusion_accounting_ai): route legacy reconcile tools through engine

When fusion_accounting_bank_rec is installed, match_bank_line_to_payments
and auto_reconcile_bank_lines now use fusion.reconcile.engine via the
BankRecAdapter, gaining precedent recording, AI suggestion superseding,
and shared validation. Legacy paths preserved for Enterprise/Community-
only installs (engine model absent -> fall back to set_line_bank_statement_line
and _try_auto_reconcile_statement_lines).

Also wraps engine.reconcile_batch's per-line loop in a savepoint so a
single bad line's DB error (e.g. check-constraint violation) no longer
poisons the whole batch transaction; the existing per-line try/except
now isolates failures as originally intended.

Made-with: Cursor

fusion_accounting_bank_rec/models/fusion_reconcile_engine.py

@@ -177,14 +177,19 @@ class FusionReconcileEngine(models.AbstractModel):
             if line.is_reconciled:
                 skipped += 1
                 continue
+            # Per-line savepoint so a single DB-level failure (e.g. a
+            # check-constraint violation on one bad line) doesn't poison
+            # the whole batch's transaction.
             try:
-                candidates = self._fetch_candidates(line)
-                picked = self._apply_strategy(line, candidates, strategy)
-                if picked:
-                    self.reconcile_one(line, against_lines=picked)
-                    reconciled += 1
-                else:
-                    skipped += 1
+                with self.env.cr.savepoint():
+                    candidates = self._fetch_candidates(line)
+                    picked = self._apply_strategy(
+                        line, candidates, strategy)
+                    if picked:
+                        self.reconcile_one(line, against_lines=picked)
+                        reconciled += 1
+                    else:
+                        skipped += 1
             except Exception as e:  # noqa: BLE001
                 errors.append({'line_id': line.id, 'error': str(e)})
                 _logger.warning(