fix(backend): resolve ESLint errors for Jest config and test setup files

- Add allowDefaultProject for JS config files in eslint.config.mjs

- Add no-console: off for test setup files

- Fix async arrow function without await in jest-e2e.setup.ts

- Remove unused eslint-disable directives

backend/jest.config.js

@@ -0,0 +1,113 @@
+/**
+ * Jest Configuration for LCBP3-DMS Backend
+ *
+ * ตาม Testing Strategy spec:
+ * - Global coverage: 70% (backend overall)
+ * - Services: 80% (business logic)
+ * - Guards/Middleware: 90%
+ * - Utilities: 95%
+ *
+ * @see specs/05-Engineering-Guidelines/05-04-testing-strategy.md
+ */
+module.exports = {
+  // File extensions
+  moduleFileExtensions: ['js', 'json', 'ts'],
+
+  // Root directory for tests
+  rootDir: 'src',
+
+  // Test file pattern
+  testRegex: '.*\\.spec\\.ts$',
+
+  // TypeScript transformation
+  transform: {
+    '^.+\\.(t|j)s$': 'ts-jest',
+  },
+
+  // Coverage configuration
+  collectCoverageFrom: [
+    '**/*.(t|j)s',
+    '!**/*.d.ts',
+    '!**/index.ts',
+    '!**/database/seeds/**',
+    '!**/database/migrations/**',
+    '!**/config/**',
+    '!**/scripts/**',
+    '!**/*.module.ts',
+  ],
+  coverageDirectory: '../coverage',
+  coveragePathIgnorePatterns: ['/node_modules/', '/test/', '/dist/'],
+
+  // Test environment
+  testEnvironment: 'node',
+
+  // Cache for faster subsequent runs
+  cacheDirectory: '.jest-cache',
+
+  // Global setup after env
+  setupFilesAfterEnv: ['../test/jest.setup.ts'],
+
+  // Transform ignore patterns (ให้ Jest ประมวลผล uuid)
+  transformIgnorePatterns: ['node_modules/(?!uuid/)'],
+
+  // Coverage thresholds ตาม Testing Strategy spec
+  coverageThreshold: {
+    global: {
+      branches: 70,
+      functions: 70,
+      lines: 70,
+      statements: 70,
+    },
+    './src/modules/*/services/*.service.ts': {
+      branches: 80,
+      functions: 80,
+      lines: 80,
+      statements: 80,
+    },
+    './src/modules/*/services/*.spec.ts': {
+      branches: 80,
+      functions: 80,
+      lines: 80,
+      statements: 80,
+    },
+    './src/common/guards/*.ts': {
+      branches: 90,
+      functions: 90,
+      lines: 90,
+      statements: 90,
+    },
+    './src/common/interceptors/*.ts': {
+      branches: 90,
+      functions: 90,
+      lines: 90,
+      statements: 90,
+    },
+    './src/common/utils/*.ts': {
+      branches: 95,
+      functions: 95,
+      lines: 95,
+      statements: 95,
+    },
+  },
+
+  // Module name mapper for path aliases
+  moduleNameMapper: {
+    '^@/(.*)$': '<rootDir>/$1',
+    '^@common/(.*)$': '<rootDir>/common/$1',
+    '^@modules/(.*)$': '<rootDir>/modules/$1',
+    '^@config/(.*)$': '<rootDir>/config/$1',
+    '^@database/(.*)$': '<rootDir>/database/$1',
+  },
+
+  // Verbose output for debugging
+  verbose: true,
+
+  // Clear mock calls between tests
+  clearMocks: true,
+
+  // Restore mock state after each test
+  restoreMocks: true,
+
+  // Maximum workers (ใช้ 50% ของ available CPUs)
+  maxWorkers: '50%',
+};