Add support for more tech stack icons

**Description:**
Expand the icon_fetcher.py name mapping to support more technologies.

Currently supported: Cursor, Claude, Next.js, Supabase, React, TypeScript, Python, Tailwind, Stripe, FastAPI, GitHub API, Vercel.

**Todo:**
- [ ] Add 20+ more popular tech stack mappings to `agents/icon_fetcher.py` (lines 25-40)
- [ ] Test with example YAML files
- [ ] Update documentation with supported technologies

**Good for:** First-time contributors, no design skills needed!

**Files to edit:** `agents/icon_fetcher.py`

**Resources:**
- SimpleIcons directory: https://simpleicons.org/
- Check slug names at: https://github.com/simple-icons/simple-icons/blob/master/slugs.md