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/Agent/AgentNodeProfileController.php

@@ -51,6 +51,7 @@ final class AgentNodeProfileController extends Controller
             : null;
 
         $payload = $request->validated();
+
         if ($parent !== null) {
             $service->assertChildCapabilityGrantsWithinParent($parent, $payload, $admin);
         }