mixmd v0 bootstrap

Markdown-first mix publishing, now under construction.

This worker is the first live slice of mixmd: one Astro app, one domain, one durable path from draft uploads to public pages.

Tonight's focus

Slice 0 and Slice 1: deploy bootstrap, D1 wiring, Kysely types, and the first API health check.

Next up

Cloudflare Access for /admin, direct-to-R2 uploads, and the draft authoring flow.