feat(fusion_accounting_ai): wire ReportsAdapter fusion paths to engine

Adds three new method families on ReportsAdapter that route through
fusion.report.engine when fusion_accounting_reports is installed:

- run_fusion_report (pnl/balance_sheet/trial_balance/general_ledger)
- get_anomalies (variance detection on engine output)
- get_commentary (LLM narrative; falls back to templated)

These coexist with the legacy ref_id-shaped run_report / export_report
API so existing reporting tools (profit_loss, balance_sheet, etc.) keep
working unchanged. FUSION_MODEL is updated to fusion.report.engine so
mode detection picks FUSION when the new engine is installed.

4 new TransactionCase tests cover the fusion + community paths.

Made-with: Cursor

fusion_accounting_reports/__manifest__.py

@@ -1,6 +1,6 @@
 {
     'name': 'Fusion Accounting Reports',
-    'version': '19.0.1.0.14',
+    'version': '19.0.1.0.15',
     'category': 'Accounting/Accounting',
     'summary': 'AI-augmented financial reports (P&L, balance sheet, trial balance, GL).',
     'description': """