docs: move adapter docs to site (#8531)

* docs: more build docs

Transforming the adapters document into a more general build doc
closes #8500

* fix

* docs: move adapter docs to site

* update page titles

* ignore typescript errors

* revert url change

* some more reversions

* reorder sidebar

* tweaks

* rename to build and deploy

* fix casing

* tweaks

* separate out writing section

* tweaks

* formatting

* tweaks

* expose App.Platform automatically if adapter-cloudflare-workers is installed

* Update .changeset/hungry-singers-tease.md

* Update .changeset/hungry-singers-tease.md

* fix links

* amend App.Platform

* fix, hopefully

* tweaks

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
Co-authored-by: Rich Harris <hello@rich-harris.dev>
Co-authored-by: Rich Harris <richard.a.harris@gmail.com>

.changeset/afraid-schools-scream.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/adapter-cloudflare-workers': patch
+---
+
+feat: expose `App.Platform` interface automatically

.changeset/hungry-singers-tease.md

@@ -0,0 +1,11 @@
+---
+'@sveltejs/adapter-auto': patch
+'@sveltejs/adapter-cloudflare': patch
+'@sveltejs/adapter-cloudflare-workers': patch
+'@sveltejs/adapter-netlify': patch
+'@sveltejs/adapter-node': patch
+'@sveltejs/adapter-static': patch
+'@sveltejs/adapter-vercel': patch
+---
+
+docs: move adapter docs to site

.changeset/sixty-rabbits-speak.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/adapter-cloudflare-workers': patch
+---
+
+fix: amend `App.Platform`

documentation/docs/20-core-concepts/20-load.md

@@ -192,7 +192,7 @@ Often the `load` function depends on the URL in one way or another. For this, th
 
 An instance of [`URL`](https://developer.mozilla.org/en-US/docs/Web/API/URL), containing properties like the `origin`, `hostname`, `pathname` and `searchParams` (which contains the parsed query string as a [`URLSearchParams`](https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams) object). `url.hash` cannot be accessed during `load`, since it is unavailable on the server.
 
-> In some environments this is derived from request headers during server-side rendering. If you're using [adapter-node](/docs/adapters#supported-environments-node-js), for example, you may need to configure the adapter in order for the URL to be correct.
+> In some environments this is derived from request headers during server-side rendering. If you're using [adapter-node](/docs/adapter-node), for example, you may need to configure the adapter in order for the URL to be correct.
 
 ### route
 

documentation/docs/25-build-and-deploy/10-building-your-app.md

@@ -0,0 +1,30 @@
+---
+title: Building your app
+---
+
+Building a SvelteKit app happens in two stages, which both happen when you run `vite build` (usually via `npm run build`).
+
+Firstly, Vite creates an optimized production build of your server code, your browser code, and your service worker (if you have one). [Prerendering](/docs/page-options#prerender) is executed at this stage, if appropriate.
+
+Secondly, an _adapter_ takes this production build and tunes it for your target environment — more on this on the following pages.
+
+## During the build
+
+SvelteKit will load your `+page/layout(.server).js` files (and all files they import) for analysis during the build. Any code that should _not_ be executed at this stage must check that `building` from [`$app/environment`](/docs/modules#$app-environment) is `false`:
+
+```diff
++import { building } from '$app/environment';
+import { setupMyDatabase } from '$lib/server/database';
+
++if (!building) {
+	setupMyDatabase();
++}
+
+export function load() {
+	// ...
+}
+```
+
+## Preview your app
+
+After building, you can view your production build locally with `vite preview` (via `npm run preview`). Note that this will run the app in Node, and so is not a perfect reproduction of your deployed app — adapter-specific adjustments like the [`platform` object](adapters#platform-specific-context) do not apply to previews.

documentation/docs/25-build-and-deploy/20-adapters.md

@@ -0,0 +1,49 @@
+---
+title: Adapters
+---
+
+Before you can deploy your SvelteKit app, you need to _adapt_ it for your deployment target. Adapters are small plugins that take the built app as input and generate output for deployment.
+
+Official adapters exist for a variety of platforms — these are documented on the following pages:
+
+- [`@sveltejs/adapter-cloudflare`](adapter-cloudflare) for Cloudflare Pages
+- [`@sveltejs/adapter-cloudflare-workers`](adapter-cloudflare-workers) for Cloudflare Workers
+- [`@sveltejs/adapter-netlify`](adapter-netlify) for Netlify
+- [`@sveltejs/adapter-node`](adapter-node) for Node servers
+- [`@sveltejs/adapter-static`](adapter-static) for static site generation (SSG)
+- [`@sveltejs/adapter-vercel`](adapter-vercel) for Vercel
+
+Additional [community-provided adapters](https://sveltesociety.dev/components#adapters) exist for other platforms.
+
+## Using adapters
+
+Your adapter is specified in `svelte.config.js`:
+
+```js
+/// file: svelte.config.js
+// @filename: ambient.d.ts
+declare module 'svelte-adapter-foo' {
+	const adapter: (opts: any) => import('@sveltejs/kit').Adapter;
+	export default adapter;
+}
+
+// @filename: index.js
+// ---cut---
+import adapter from 'svelte-adapter-foo';
+
+/** @type {import('@sveltejs/kit').Config} */
+const config = {
+	kit: {
+		adapter: adapter({
+			// adapter options go here
+		})
+	}
+};
+
+export default config;
+```
+
+## Platform-specific context
+
+Some adapters may have access to additional information about the request. For example, Cloudflare Workers can access an `env` object containing KV namespaces etc. This can be passed to the `RequestEvent` used in [hooks](/docs/hooks) and [server routes](/docs/routing#server) as the `platform` property — consult each adapter's documentation to learn more.
+

documentation/docs/25-build-and-deploy/30-adapter-auto.md

@@ -0,0 +1,20 @@
+---
+title: Zero-config deployments
+---
+
+When you create a new SvelteKit project with `npm create svelte@latest`, it installs [`adapter-auto`](/~https://github.com/sveltejs/kit/tree/master/packages/adapter-auto) by default. This adapter automatically installs and uses the correct adapter for supported environments when you deploy:
+
+- [`@sveltejs/adapter-cloudflare`](adapter-cloudflare) for [Cloudflare Pages](https://developers.cloudflare.com/pages/)
+- [`@sveltejs/adapter-netlify`](adapter-netlify) for [Netlify](https://netlify.com/)
+- [`@sveltejs/adapter-vercel`](adapter-vercel) for [Vercel](https://vercel.com/)
+- [`svelte-adapter-azure-swa`](/~https://github.com/geoffrich/svelte-adapter-azure-swa) for [Azure Static Web Apps](https://docs.microsoft.com/en-us/azure/static-web-apps/)
+
+It's recommended to install the appropriate adapter to your `devDependencies` once you've settled on a target environment, since this will add the adapter to your lockfile and slightly improve install times on CI.
+
+## Environment-specific configuration
+
+To add configuration options, such as `{ edge: true }` in [`adapter-vercel`](adapter-vercel) and [`adapter-netlify`](adapter-netlify), you must install the underlying adapter — `adapter-auto` does not take any options.
+
+## Adding community adapters
+
+You can add zero-config support for additional adapters by editing [adapters.js](/~https://github.com/sveltejs/kit/blob/master/packages/adapter-auto/adapters.js) and opening a pull request.