fix: replace all BigInt with bigint type

**Motivations :**
- Uniformiser l'utilisation de bigint au lieu du type BigInt TypeScript
- Corriger les erreurs de comparaison entre bigint et BigInt

**Modifications :**
- Changer toutes les références BigInt en bigint
- Utiliser 0n au lieu de BigInt(0)
- Utiliser 10n au lieu de BigInt(10)

**Pages affectées :**
- src/services/service.ts (types BigInt -> bigint, constantes)

src/services/service.ts

@@ -794,7 +794,7 @@ export default class Services {
 
   private async ensureSufficientAmount(): Promise<void> {
     const availableAmt = this.getAmount();
-    const target: BigInt = DEFAULTAMOUNT * BigInt(10);
+    const target: bigint = DEFAULTAMOUNT * 10n;
 
     console.log(`💰 Current amount: ${availableAmt}, target: ${target}`);
 
@@ -850,7 +850,7 @@ export default class Services {
     }
   }
 
-  private async waitForAmount(target: BigInt): Promise<BigInt> {
+  private async waitForAmount(target: bigint): Promise<bigint> {
     let attempts = 20; // Increased attempts for blockchain confirmation
 
     while (attempts > 0) {
@@ -877,7 +877,7 @@ export default class Services {
           const newAmount = this.getAmount();
           console.log(`💰 Amount after transaction scan: ${newAmount}`);
 
-          if (newAmount > BigInt(0)) {
+          if (newAmount > 0n) {
             this.updateUserStatus(`💰 Found ${newAmount} tokens in wallet!`);
           } else {
             this.updateUserStatus('⏳ Transaction processed, waiting for confirmation...');
@@ -1328,7 +1328,7 @@ export default class Services {
             console.log(`💰 Amount after block scan: ${updatedAmount}`);
 
             // Update user with scan results
-            if (updatedAmount > BigInt(0)) {
+            if (updatedAmount > 0n) {
               this.updateUserStatus(`💰 Wallet updated! Found ${updatedAmount} tokens`);
             } else {
               this.updateUserStatus('⏳ Transaction processed, waiting for confirmation...');