feat: add NPM support for global installation and Node.js ecosystem compatibility

[reizhafajrian]

Description

Overview

This PR adds NPM support to the project, allowing users to install code-review-graph globally via npm install -g code-review-graph.

While the core logic remains in Python, this addition provides a seamless experience for developers in the Node.js ecosystem, which is common for many AI coding tools (like Claude Code, Cursor, etc.).

Key Changes

• Node.js Wrapper: Added bin/cli.js to act as a bridge, automatically locating the Python environment and forwarding commands.
• Automated Setup: Included a scripts/npm-postinstall.js script that automatically creates an isolated Python virtual environment (.venv) and installs all necessary dependencies upon running npm install.
• Packaging: Configured package.json with binary mappings (code-review-graph and crg) and ensured all required Python assets are bundled.
• Documentation: Updated README.md and all translations (zh-CN, ja-JP, ko-KR, hi-IN) to include the new NPM installation method.

Why this is beneficial

• Easier Installation: Users don't need to manually manage Python virtual environments or paths if they prefer using npm.
• Broader Adoption: Makes the tool more accessible to frontend and full-stack developers who primarily use Node.js tools.
• Improved DX: The post-install script handles the heavy lifting of dependency management automatically.

How to test

1. Clone this branch/fork.
2. Run npm install -g . from the root directory.
3. Verify that code-review-graph --version or crg status works correctly in any directory.