Add interactive D3.js visualization page with GitHub Pages auto-deployment

[Copilot]

The repo had no deployable content — only a bare README. This adds a fully interactive visualization site and wires up automated GitHub Pages deployment.

Changes

index.html

Single-page D3.js v7 app with four chart types, all loaded from CDN (no build step):

• Bar Chart — monthly sales by category; dropdown filter; animated entry; hover tooltips
• Line Chart — annual avg. temperature (2015–2024) for 3 cities; per-city toggle buttons; animated path draw
• Scatter Plot — GDP per capita vs. life expectancy for 20 countries; bubble size ∝ population; live size slider; color-coded by region
• Pie/Donut Chart — global energy mix; click-to-highlight slices; center label

.github/workflows/deploy-pages.yml

Auto-deploys repo root to GitHub Pages on every push to main using the official Actions suite (configure-pages, upload-pages-artifact, deploy-pages). Also supports manual dispatch.

on:
  push:
    branches: [main]
  workflow_dispatch:

One-time setup required: enable GitHub Pages in Settings → Pages → Source → GitHub Actions.

README.md

Updated with live site URL, chart inventory, tech stack, and Pages activation instructions.

Original prompt

我想通过Github Pages托管项目仓库中的可视化成果