astro 2.7.0

#7353 76fcdb84d Thanks @bholmesdev! - Remove legacy handling for MDX content collections. Ensure you are using @astrojs/mdx v0.18 or above.
#7385 8e2923cc6 Thanks @ematipico! - Astro.locals is now exposed to the adapter API. Node Adapter can now pass in a locals object in the SSR handler middleware.
#7220 459b5bd05 Thanks @ematipico! - Shipped a new SSR build configuration mode: split. When enabled, Astro will "split" the single entry.mjs file and instead emit a separate file to render each individual page during the build process.

These files will be emitted inside dist/pages, mirroring the directory structure of your page files in src/pages/, for example:
```
├── pages
│   ├── blog
│   │   ├── entry._slug_.astro.mjs
│   │   └── entry.about.astro.mjs
│   └── entry.index.astro.mjs
```
To enable, set build.split: true in your Astro config:
```
// src/astro.config.mjs
export default defineConfig({
  output: 'server',
  adapter: node({
    mode: 'standalone',
  }),
  build: {
    split: true,
  },
});
```

#7438 30bb36371 Thanks @bluwy! - Fix astro:build:setup hook updateConfig utility, where the configuration wasn't correctly updated when the hook was fired.
#7436 3943fa390 Thanks @kossidts! - Fix an issue related to the documentation. Destructure the argument of the function to customize the Astro dev server based on the command run.
#7424 7877a06d8 Thanks @bholmesdev! - Update internal types for more stable builds for Astro maintainers.
#7427 e314a04bf Thanks @ematipico! - Correctly emit the middleware code during the build phase. The file emitted is now dist/middleware.mjs
#7423 33cdc8622 Thanks @bmenant! - Ensure injected /_image endpoint for image optimization is not prerendered on hybrid output.