fix(entraid): correct package entry point structure

Add root index.ts to properly expose package exports through `@redis/entraid`
rather than requiring users to import through `@redis/entraid/dist/lib`.
This maintains backward compatibility while providing the correct package
structure where all exports are available from the package root.

- Add /index.ts that re-exports all from /lib/index.ts
- Preserve existing /lib/index.ts structure
- Update docs

Author: bobymicroby

packages/entraid/README.md

@@ -39,7 +39,7 @@ The first step to using @redis/entraid is choosing the right credentials provide
 
 ```typescript
 import { createClient } from '@redis/client';
-import { EntraIdCredentialsProviderFactory } from '@redis/entraid/dist/lib/entra-id-credentials-provider-factory';
+import { EntraIdCredentialsProviderFactory } from '@redis/entraid';
 
 const provider = EntraIdCredentialsProviderFactory.createForClientCredentials({
   clientId: 'your-client-id',

packages/entraid/index.ts

@@ -0,0 +1 @@
+export * from './lib/index'