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

Edit the name mapping in agents/icon_fetcher.py lines 25-40. Use the SimpleIcons directory and slugs.md to find correct icon slugs. Test by running the script with example YAML files to verify new icons appear. Update the documentation to list the newly supported technologies.

Written by the indexing model from the issue text.