v0.3.1

• llms.txt and markdown responses send Cache-Control: public, max-age=0, s-maxage=3600 (Kinsta's own policy for HTML pages) unless one is already set, and never for logged-in users or previews, so Kinsta's edge caches them like pages. Change with gds/llms/cache_control. (#15)
• README: on Kinsta, exclude txt and md from the CDN, which otherwise caches both for a year by extension.