feat: 添加 Node.js SDK 的构建和测试支持，更新文档，移除过时的测试文件

[MasonChow]

No description provided.

[Copilot]

Pull Request Overview

This PR adds comprehensive Node.js SDK build and test support, updates documentation, and removes outdated test files. The changes include setting up modern ESM-based tooling with Vite/Vitest, creating a library mode build system, and migrating from Rust WASM tests to JavaScript-based testing.

• Sets up Vite build configuration for library mode ESM output
• Adds Vitest configuration with WASM plugin support for testing
• Creates TypeScript wrapper layer for better API ergonomics
• Removes legacy Rust WASM test files in favor of JavaScript tests

Reviewed Changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
scripts/build-wasm-node.sh	Updates build script to use bundler target and clean output directory
crates/node_sdk/vitest.config.mjs	Adds Vitest configuration with WASM plugins and test coverage setup
crates/node_sdk/vite.config.mjs	Adds Vite build configuration for ESM library mode output
crates/node_sdk/tests/wasm_smoke.rs	Removes legacy Rust WASM test file
crates/node_sdk/tests/wasm_extended.rs	Removes legacy Rust WASM test file
crates/node_sdk/tests/test_basic.test.mjs	Adds comprehensive JavaScript test suite for the SDK
crates/node_sdk/src/index.ts	Creates TypeScript wrapper layer with init function and helper methods
crates/node_sdk/package.json	Adds package configuration with ESM exports and build scripts
crates/node_sdk/README.md	Updates documentation with new library mode usage and migration guide

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