v0.3.0 — Reading surfaces: a table of contents, syntax-highlighted code, image carousels, and the first steps off Astro DB

Two weeks spent making long-form content actually readable — a reading-position ToC on every guide, code blocks that read in the house palette, carousels for screenshot sequences — and one layout bug, found by measurement after three wrong guesses, that had been bleeding every page off the right edge the entire time.