feat: enhance agent settlement features and improve data access controls

- Added new section in AGENTS.md detailing learned workspace facts for better understanding of settlement processes.
- Updated AgentNodeDestroyController to remove unnecessary checks for admin users.
- Enhanced AgentSettlement controllers to assert permissions for finance adjustments and bill operations.
- Improved query scopes in AgentSettlement services to ensure proper data access based on admin roles.
- Refactored methods in SettlementPartyEnrichment for better bill row enrichment and data handling.
- Introduced new methods in AdminAgentSettlementScope for managing agent node visibility and finance adjustments.

app/Services/AgentSettlement/AgentSettlementPeriodCloseService.php

@@ -79,6 +79,7 @@ final class AgentSettlementPeriodCloseService
                     ->from('share_ledger as sl')
                     ->join('players as p', 'p.id', '=', 'sl.player_id')
                     ->where('p.site_code', $siteCode)
+                    ->whereNull('sl.settlement_period_id')
                     ->whereBetween('sl.settled_at', [$periodStart, $periodEnd]);
             })
             ->update(['settlement_period_id' => $periodId]);