Refactor ESLint configuration and update code formatting: Standardize quotes in eslint.config.mjs, next.config.js, and various TypeScript files for consistency. Add Prettier as a dependency and include formatting scripts in package.json. Clean up unnecessary whitespace in multiple files to enhance code readability.

app/api/admin/users/[id]/route.ts

@@ -99,7 +99,7 @@ export async function PUT(
       // Si le niveau est modifié directement, utiliser cette valeur
       const targetLevel = Math.max(1, level);
       updateData.level = targetLevel;
-      
+
       // Recalculer le maxXp pour le nouveau niveau
       // Formule: maxXp = 5000 * (1.2 ^ (level - 1))
       let calculatedMaxXp = 5000;
@@ -107,7 +107,7 @@ export async function PUT(
         calculatedMaxXp = Math.floor(calculatedMaxXp * 1.2);
       }
       updateData.maxXp = calculatedMaxXp;
-      
+
       // Réinitialiser l'XP si le niveau change directement (sauf si on modifie aussi l'XP)
       if (targetLevel !== user.level && xpDelta === undefined) {
         updateData.xp = 0;
@@ -196,4 +196,3 @@ export async function DELETE(
     );
   }
 }
-