v0.1.0b3

prepare 0.1.0b3 release (add Documentation project URL)

Django Packages reads a package's documentation link from PyPI project_urls
(keys Documentation/Docs/docs/documentation); without it the grid showed no
docs despite docs/ shipping in the wheel. Add the Documentation URL and bump.

Co-Authored-By: Claude Opus 4.8 (1M context) noreply@anthropic.com