astro 1.9.0

#5666 bf210f784 Thanks @bholmesdev! - Correctly handle spaces and capitalization in src/content/ file names. This introduces github-slugger for slug generation to ensure slugs are usable by getStaticPaths. Changes:
- Resolve spaces and capitalization: collection/Entry With Spaces.md becomes collection/entry-with-spaces.
- Truncate /index paths to base URL: collection/index.md becomes collection

#5720 fe316be86 Thanks @umarov! - Do not add base path to a hoisted script body
#5706 c2844a79c Thanks @bluwy! - Add preact and sitemap integration to config load external list
#5700 3aa3e00a6 Thanks @bholmesdev! - Fix import.meta.env.DEV always being set to true when using Content Collections