feat: add Python/Node.js code tabs to all doc pages

feat: add Mermaid diagram support via vitepress-plugin-mermaid

fix: correct base path case to match repo name Agentic-AI-101

fix: enable GitHub Pages auto-enablement in workflow

feat: add VitePress docs site with GitHub Pages deployment

docs: add complete book content chapters 5-15 and appendix with Python and Node.js examples

fix: fixed mermaid syntax

feat: updated 04-memory-context.md

feat: 03-first-agent-nodejs.md

feat: updated 03-first-agent.md and 03-first-agent-nodejs.md

feat: updated 03-first-agent.md

feat: updated 03-first-agent.md

feat: 02-tools-tech-stack.md updated

feat: 02-tools-tech-stack.md updated

feat: added flowcharts