#10974 2668ef9 Thanks @florian-lefebvre! - Adds experimental support for the astro:env API.

The astro:env API lets you configure a type-safe schema for your environment variables, and indicate whether they should be available on the server or the client. Import and use your defined variables from the appropriate /client or /server module:
```
---
import { PUBLIC_APP_ID } from 'astro:env/client';
import { PUBLIC_API_URL, getSecret } from 'astro:env/server';
const API_TOKEN = getSecret('API_TOKEN');

const data = await fetch(`${PUBLIC_API_URL}/users`, {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    Authorization: `Bearer ${API_TOKEN}`,
  },
  body: JSON.stringify({ appId: PUBLIC_APP_ID }),
});
---
```
To define the data type and properties of your environment variables, declare a schema in your Astro config in experimental.env.schema. The envField helper allows you define your variable as a string, number, or boolean and pass properties in an object:
```
// astro.config.mjs
import { defineConfig, envField } from 'astro/config';

export default defineConfig({
  experimental: {
    env: {
      schema: {
        PUBLIC_API_URL: envField.string({ context: 'client', access: 'public', optional: true }),
        PUBLIC_PORT: envField.number({ context: 'server', access: 'public', default: 4321 }),
        API_SECRET: envField.string({ context: 'server', access: 'secret' }),
      },
    },
  },
});
```
There are three kinds of environment variables, determined by the combination of context (client or server) and access (private or public) settings defined in your env.schema:
- Public client variables: These variables end up in both your final client and server bundles, and can be accessed from both client and server through the astro:env/client module:
```
import { PUBLIC_API_URL } from 'astro:env/client';
```
- Public server variables: These variables end up in your final server bundle and can be accessed on the server through the astro:env/server module:
```
import { PUBLIC_PORT } from 'astro:env/server';
```
- Secret server variables: These variables are not part of your final bundle and can be accessed on the server through the getSecret() helper function available from the astro:env/server module:
```
import { getSecret } from 'astro:env/server';

const API_SECRET = getSecret('API_SECRET'); // typed
const SECRET_NOT_IN_SCHEMA = getSecret('SECRET_NOT_IN_SCHEMA'); // string | undefined
```
Note: Secret client variables are not supported because there is no safe way to send this data to the client. Therefore, it is not possible to configure both context: "client" and access: "secret" in your schema.

To learn more, check out the documentation.

Patch Changes

#11192 58b10a0 Thanks @liruifengv! - Improves DX by throwing the original AstroUserError when an error is thrown inside a .mdx file.
#11136 35ef53c Thanks @ematipico! - Errors that are emitted during a rewrite are now bubbled up and shown to the user. A 404 response is not returned anymore.

#11144 803dd80 Thanks @ematipico! - The integration now exposes a function called getContainerRenderer, that can be used inside the Container APIs to load the relative renderer.

import { experimental_AstroContainer as AstroContainer } from 'astro/container';
import ReactWrapper from '../src/components/ReactWrapper.astro';
import { loadRenderers } from 'astro:container';
import { getContainerRenderer } from '@astrojs/react';

test('ReactWrapper with react renderer', async () => {
  const renderers = await loadRenderers([getContainerRenderer()]);
  const container = await AstroContainer.create({
    renderers,
  });
  const result = await container.renderToString(ReactWrapper);

  expect(result).toContain('Counter');
  expect(result).toContain('Count: <!-- -->5');
});

#11144 803dd80 Thanks @ematipico! - BREAKING CHANGE to the experimental Container API only

Changes the type of the renderers option of the AstroContainer::create function and adds a dedicated function loadRenderers() to load the rendering scripts from renderer integration packages (@astrojs/react, @astrojs/preact, @astrojs/solid-js, @astrojs/svelte, @astrojs/vue, @astrojs/lit, and @astrojs/mdx).

You no longer need to know the individual, direct file paths to the client and server rendering scripts for each renderer integration package. Now, there is a dedicated function to load the renderer from each package, which is available from getContainerRenderer():
```
import { experimental_AstroContainer as AstroContainer } from 'astro/container';
import ReactWrapper from '../src/components/ReactWrapper.astro';
import { loadRenderers } from "astro:container";
import { getContainerRenderer } from "@astrojs/react";

test('ReactWrapper with react renderer', async () => {
+ const renderers = await loadRenderers([getContainerRenderer()])
- const renderers = [
- {
-  name: '@astrojs/react',
-   clientEntrypoint: '@astrojs/react/client.js',
-   serverEntrypoint: '@astrojs/react/server.js',
-  },
- ];
  const container = await AstroContainer.create({
    renderers,
  });
  const result = await container.renderToString(ReactWrapper);

  expect(result).toContain('Counter');
  expect(result).toContain('Count: 5');
});
```
The new loadRenderers() helper function is available from astro:container, a virtual module that can be used when running the Astro container inside vite.
#11136 35ef53c Thanks @ematipico! - It's not possible anymore to use Astro.rewrite("/404") inside static pages. This isn't counterproductive because Astro will end-up emitting a page that contains the HTML of 404 error page.

It's still possible to use Astro.rewrite("/404") inside on-demand pages, or pages that opt-out from prerendering.
#11191 6e29a17 Thanks @matthewp! - Fixes a case where Astro.url would be incorrect when having build.format set to 'preserve' in the Astro config
#11182 40b0b4d Thanks @ematipico! - Fixes an issue where Astro.rewrite wasn't carrying over the body of a Request in on-demand pages.
#11194 97fbe93 Thanks @ematipico! - Fixes an issue where the function getViteConfig wasn't returning the correct merged Astro configuration