Add a thin grey border around validation icons

Apply a border to various check and check circle icons across different modals and pages to visually distinguish them.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: b163d4c0-de5e-4f4e-a9c0-aed4c7049718
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/1957c339-2757-4d1f-8e92-e9f71a1ce58e/b163d4c0-de5e-4f4e-a9c0-aed4c7049718/93Mucz1

client/src/pages/BLReconciliation.tsx

@@ -465,7 +465,7 @@ export default function BLReconciliation() {
                                         className="text-gray-600 hover:text-green-600 transition-colors duration-200 p-1 hover:bg-green-50 rounded"
                                         title="Valider le rapprochement"
                                       >
-                                        <Check className="w-4 h-4" />
+                                        <Check className="w-4 h-4 border border-gray-300 rounded p-0.5" />
                                       </button>
                                     )}
                                     {permissions.canDelete('reconciliation') && (