feat: enhance agent management and validation logic

- Updated AGENTS.md to clarify agent account restrictions and permissions.
- Implemented checks in AgentNodeAdminUserStoreController and AgentNodeRoleStoreController to restrict admin user and role creation to the agent's own node.
- Enhanced validation in AdminPlayerStoreController and AdminPlayerUpdateController to enforce credit limit and rebate rate rules based on player funding mode.
- Refactored various request classes to utilize shared admin account field rules for consistency.
- Improved error handling in services related to credit allocation and rebate limits to ensure proper validation and messaging.

app/Http/Controllers/Api/V1/Admin/AgentSettlement/AgentSettlementReportShowController.php

@@ -33,7 +33,7 @@ final class AgentSettlementReportShowController extends Controller
         abort_unless(in_array($type, self::TYPES, true), 404);
 
         if ($type === 'platform_pnl' && AdminAgentScope::primaryAgentNode($admin) !== null) {
-            abort(403, 'agent_cannot_view_platform_pnl');
+            abort(403, 'admin.agent_cannot_view_platform_pnl');
         }
 
         $periodId = (int) $request->query('settlement_period_id', 0);