Add .github/FUNDING.yml to enable the Sponsor button, refocus the
README on selfhoster users with a Highlights section and a Supporting
Silo section, and move contributor-facing content (dev workflow, make
targets, migrations, tests, project structure) into DEVELOPMENT.md.
AI-use disclosure: written with Claude Code.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
