Add initial setup for Fumadocs documentation migration

- Created new directory structure for documentation under `/docs2`.
- Added `.gitignore` to exclude build artifacts and dependencies.
- Introduced `package.json`, `next.config.mjs`, and `postcss.config.mjs` for project configuration.
- Implemented MDX components in `mdx-components.tsx` for rendering documentation.
- Migrated existing documentation content and created new files for auto-updater and other features.
- Established compatibility layer for Mintlify components in `mintlify-compat.tsx`.
- Set up OpenAPI documentation in `openapi.json`.
- Updated README and migration guide to reflect new structure and usage instructions.
- Ensured all components and pages are ready for development and deployment with Fumadocs.

docs2/components/api-page.tsx

@@ -0,0 +1,7 @@
+import { openapi } from '@/lib/openapi';
+import { createAPIPage } from 'fumadocs-openapi/ui';
+import client from './api-page.client';
+
+export const APIPage = createAPIPage(openapi, {
+  client,
+});