feat(tests): integrate Vitest for testing framework and add test scripts

- Added Vitest as a dependency for improved testing capabilities.
- Updated package.json with new test scripts for running tests, watching, and coverage reporting.
- Configured ESLint to recognize test runner scripts and included them in the linting process.
- Modified tsconfig.json to include Vitest types for better TypeScript support in tests.

vitest.config.ts

@@ -0,0 +1,44 @@
+import { defineConfig } from 'vitest/config';
+import path from 'path';
+
+// Solution: créer un mock de postcss.config.mjs pour les tests
+// En renommant temporairement le fichier ou en créant une config vide
+
+export default defineConfig({
+  test: {
+    globals: true,
+    environment: 'node',
+    include: ['src/**/__tests__/**/*.test.ts'],
+    setupFiles: ['./src/services/__tests__/setup.ts'],
+    // Afficher plus de détails dans la sortie
+    reporters: ['verbose'],
+    // Afficher les tests qui passent aussi
+    silent: false,
+    coverage: {
+      provider: 'v8',
+      reporter: ['text', 'json', 'html'],
+      exclude: [
+        'node_modules/',
+        'src/**/__tests__/**',
+        '**/*.config.*',
+        '**/dist/**',
+      ],
+      // Afficher les fichiers non couverts
+      reportOnFailure: true,
+      // Afficher plus de détails
+      all: false,
+    },
+  },
+  resolve: {
+    alias: {
+      '@': path.resolve(__dirname, './src'),
+    },
+  },
+  // Désactiver le traitement CSS pour éviter PostCSS
+  // Le fichier postcss.config.mjs est renommé par le script test-runner.js
+  css: {
+    modules: {
+      localsConvention: 'camelCase',
+    },
+  },
+});