#15950 acce5e8 Thanks @matthewp! - Fixes a build regression in projects with multiple frontend integrations where server:defer server islands could fail at runtime when all pages are prerendered.
#15988 c93b4a0 Thanks @ossaidqadri! - Fix styles from dynamically imported components not being injected on first dev server load.
#15968 3e7a9d5 Thanks @chasemccoy! - Fixes renderMarkdown in custom content loaders not resolving images in markdown content. Images referenced in markdown processed by renderMarkdown are now correctly optimized, matching the behavior of the built-in glob() loader.
#15990 1e6017f Thanks @ematipico! - Fixes an issue where Astro.currentLocale would always be the default locale instead of the actual one when using a dynamic route like [locale].astro or [locale]/index.astro. It now resolves to the correct locale from the URL.
#15990 1e6017f Thanks @ematipico! - Fixes an issue where visiting an invalid locale URL (e.g. /asdf/) would show the content of a dynamic [locale] page with a 404 status code, instead of showing your custom 404 page. Now, the correct 404 page is rendered when the locale in the URL doesn't match any configured locale.
#15960 1d84020 Thanks @matthewp! - Fixes Cloudflare dev server islands with prerenderEnvironment: 'node' by sharing the serialized manifest encryption key across dev environments and routing server island requests through the SSR runtime.
#15735 9685e2d Thanks @fa-sharp! - Fixes an EventEmitter memory leak when serving static pages from Node.js middleware.

When using the middleware handler, requests that were being passed on to Express / Fastify (e.g. static files / pre-rendered pages / etc.) weren't cleaning up socket listeners before calling next(), causing a memory leak warning. This fix makes sure to run the cleanup before calling next().