feat(fusion_accounting_ai): 5 new financial reports AI tools

Adds financial_reports.py tools module with 5 fusion-engine-routed
tools registered in TOOL_DISPATCH:

- fusion_run_report
- fusion_get_anomalies
- fusion_generate_commentary
- fusion_drill_down_report_line
- fusion_compare_periods

Each tool guards on 'fusion.report.engine' being in the registry and
otherwise returns a structured error so the chat agent can surface a
clear "module not installed" message.

6 new TransactionCase tests (including a TOOL_DISPATCH registration
sanity check).

Made-with: Cursor

fusion_accounting_reports/__manifest__.py

@@ -1,6 +1,6 @@
 {
     'name': 'Fusion Accounting Reports',
-    'version': '19.0.1.0.15',
+    'version': '19.0.1.0.16',
     'category': 'Accounting/Accounting',
     'summary': 'AI-augmented financial reports (P&L, balance sheet, trial balance, GL).',
     'description': """