Add ai-heatmap to README as a community project

[seunggabi]

Summary

I'd like to suggest adding ai-heatmap to the ccusage README as a community/ecosystem project.

What is ai-heatmap?

ai-heatmap generates a GitHub-style contribution heatmap for your AI usage costs, powered by ccusage data.

• Renders an interactive heatmap (GitHub Pages) and a dynamic SVG (Vercel API)
• Shows daily cost, tokens, cache hit rate, and per-model breakdown via tooltips
• One-command setup: npx ai-heatmap@latest init
• Embeddable SVG for any README

Links: npm · GitHub

Suggested placement

A new "Community Projects" (or "Built with ccusage") section after the "ccusage Family" section would be a natural fit — keeping the official family tools separate while showcasing third-party projects that build on ccusage.

Example:

## Community Projects

### 🗓️ [ai-heatmap](https://github.com/seunggabi/ai-heatmap) - GitHub-style Heatmap for AI Usage

Visualize your Claude Code spending as a GitHub-style contribution heatmap. Generates interactive dashboards (GitHub Pages) and embeddable SVG images (Vercel) from ccusage data.

Happy to open a PR if you're open to this. Thank you for building ccusage!