docs: add SvelteKit framework guide and fix baseUrl parameter in Next… (#91)

* docs: add SvelteKit framework guide and fix baseUrl parameter in Next.js guide

* docs: remove reference to non-existent random value generation button

* add community callout

---------

Co-authored-by: Shawn Erquhart <shawn@erquh.art>

Author: mmailaender

docs/content/docs/framework-guides/meta.json

@@ -1,5 +1,5 @@
 {
   "title": "Framework Guides",
-  "pages": ["react", "expo", "tanstack-start", "next"],
+  "pages": ["react", "expo", "tanstack-start", "next", "sveltekit"],
   "defaultOpen": true
 }

docs/content/docs/framework-guides/next.mdx

@@ -65,7 +65,7 @@ description: Install and configure Convex + Better Auth for Next.js.
   <div className="fd-step">
     ### Set environment variables
 
-    Generate a secret for encryption and generating hashes. Use the command below if you have openssl installed, or use the button to generate a random value instead. Or generate your own however you like.
+    Generate a secret for encryption and generating hashes. Use the command below if you have openssl installed, or generate your own however you like.
 
     ```shell
     npx convex env set BETTER_AUTH_SECRET=$(openssl rand -base64 32)