test: added integration and unit testing for acpContractClientV2 (#113)

* test: added unit testing for acpContractClientV2

- installed and configured jest and babel for test environment
- created unit testing scripts for acpContractClientV2

* test: completed unit tests for acpContractClientV2.ts

- removed previous helper file under test/
- updated ES2016 to ES2020 for usage of BigInt
- updated vp sdk to latest version

* test: completed integration tests for acpContractClientV2

- added the standard env.ts file to load variables

* fix: added README.md and .env.sample

Author: JohnsonChin1009

babel.config.js

@@ -0,0 +1,6 @@
+module.exports = {
+  presets: [
+    ['@babel/preset-env', { targets: { node: 'current' } }],
+    '@babel/preset-typescript',
+  ],
+};

jest.config.js

@@ -0,0 +1,24 @@
+module.exports = {
+  testEnvironment: 'node',
+  roots: ['<rootDir>/test'],
+  testMatch: ['**/*.test.ts'],
+  collectCoverageFrom: [
+    'src/**/*.ts',
+    '!src/**/*.d.ts',
+    '!src/index.ts',
+  ],
+  coverageDirectory: 'coverage',
+  coverageReporters: ['text', 'lcov', 'html'],
+  moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json', 'node'],
+  transform: {
+    '^.+\\.(ts|tsx|js|jsx)$': 'babel-jest',
+  },
+  transformIgnorePatterns: [
+    'node_modules/(?!(@account-kit|@aa-sdk|viem|socket\\.io-client)/)',
+  ],
+  moduleNameMapper: {
+    '^(\\.{1,2}/.*)\\.js$': '$1',
+  },
+  // Force exit after tests complete (needed because AcpClient maintains persistent connections)
+  forceExit: true,
+};