Refactor: Convert legacy application to docs-only mode (#599)

This PR transforms our legacy Next.js application to serve only
documentation content by:

- Removing dashboard components and pages
- Stripping authentication requirements
- Maintaining documentation routes and content
- Preparing for proxy integration with new dashboard

### Technical changes
- Removed auth-required wrappers from documentation pages
- Eliminated dashboard-specific components and routes
- Removed unused dependencies related to dashboard functionality
- Updated application configs & sitemap.xml to support being proxied by
new dashboard app

### Testing
- Verified all documentation pages render correctly without auth
- Confirmed navigation works as expected
- Tested proxy integration with new dashboard application

### Next steps
1. Once merged, the new dashboard will proxy to this application for
documentation content
2. In the future, we'll migrate documentation to the new system
completely

Author: ben-fornefeld

apps/web/next.config.mjs

@@ -71,17 +71,6 @@ const nextConfig = {
     config.cache.version = config.cache.version + delimiter + codeFilesHash
     return config
   },
-  async rewrites() {
-    return {
-      afterFiles: [
-        {
-          source: '/ingest/:path*',
-          destination: 'https://app.posthog.com/:path*',
-          // BEWARE: setting basePath will break the analytics proxy
-        },
-      ],
-    }
-  },
   async redirects() {
     return [
       {

apps/web/package.json

@@ -53,7 +53,6 @@
     "mdx-annotations": "^0.1.1",
     "next": "14.2.25",
     "next-themes": "^0.2.1",
-    "posthog-js": "^1.148.0",
     "react": "18.2.0",
     "react-dom": "18.2.0",
     "react-highlight-words": "^0.20.0",