Docs/improve framework docs

[kevinccbsg]

This pull request introduces official documentation and example support for integrating TWD with Astro, alongside improvements to framework integration guidance and updates to CI and documentation. The most significant changes include a new Astro example app, a comprehensive framework integration guide, and enhanced documentation with updated test examples and images.

Astro Framework Integration:

• Added a full-featured Astro example app in examples/astro-example, including configuration files (astro.config.mjs, tsconfig.json, .gitignore, package.json), layout and component files, and a sample TWD test. This demonstrates how to integrate TWD with Astro and React, including HMR support for test files. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
• Added a new "Framework Integration" documentation page (docs/frameworks.md) with detailed setup instructions for Vite-based React, Create React App, and Astro, plus a roadmap for Vue and Angular support.
• Updated the documentation navigation to include the new "Framework Integration" section.

Documentation and Examples:

• Improved the "Quick Example" and installation sections in the docs and README to use more relevant test examples and added images showing the TWD sidebar in action. [1] [2]

Continuous Integration:

• Added a CI workflow for the tutorial example app and updated the main CI workflow to test Node.js 25.x. [1] [2]