fix: enhance Fusion Claims Intelligence AI with client status and billing period tools

- Fix _read_group override crash (dict_values not subscriptable) in sale_order.py
- Migrate _fc_tool_claims_stats from deprecated read_group() to _read_group() API
- Enrich client details tool with funding history, invoice status, prev-funded devices
- Add Client Status Lookup tool (search by name, returns orders/invoices/next steps)
- Add ADP Billing Period tool (invoiced amounts, paid/unpaid, submission deadlines)
- Update AI agent system prompt with all 5 tools and usage examples

fusion_claims/models/sale_order.py

@@ -1836,7 +1836,8 @@ class SaleOrder(models.Model):
             domain, groupby=groupby, aggregates=aggregates,
             having=having, offset=offset, limit=limit, order=order,
         )
-        if groupby and groupby[0] == 'x_fc_adp_application_status':
+        groupby_list = list(groupby) if not isinstance(groupby, (list, tuple)) else groupby
+        if groupby_list and groupby_list[0] == 'x_fc_adp_application_status':
             status_order = self._STATUS_ORDER
             result = sorted(result, key=lambda r: status_order.get(r[0], 999))
         return result