Fix the funding email link in the README

[Email](funding@fallout.build) renders as a relative link, not a mailto —
GitHub resolves it against the repo root and 404s.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: ChrisonSimtian

README.md

@@ -94,7 +94,7 @@ More styles and wordings, plus the logo source, are in [docs/badge.md](docs/badg
 
 ## Sponsorship
 
-Fallout is volunteer-run. We happily accept sponsorship via Github, or if you want to financially support us through other channels, please reach out to us via [Email](funding@fallout.build). We will try our best to be as transparent as possible about the running [`Costs`](docs/costs.md) of this project and where your contributions go. We currently cant offer you a not-for-profit donation statement, as we're not set up as a Not-For-Profit organisation (yet).
+Fallout is volunteer-run. We happily accept sponsorship via Github, or if you want to financially support us through other channels, please reach out to us via [Email](mailto:funding@fallout.build). We will try our best to be as transparent as possible about the running [`Costs`](docs/costs.md) of this project and where your contributions go. We currently cant offer you a not-for-profit donation statement, as we're not set up as a Not-For-Profit organisation (yet).
 
 ## Credits