docs(readme): clarify new repository location and package path for archived library

Author: CorentinTh

README.md

@@ -1,5 +1,6 @@
 > [!IMPORTANT]
-> The source code of this library has been moved to the [Papra](https://github.com/papra-hq/papra) monorepo repository.
+> The source code of this library has been moved to the [Papra](https://github.com/papra-hq/papra/tree/main/packages/lecture) monorepo repository, under the `packages/lecture` package path.
+> 
 > This repository is now archived.
 
 # @papra/lecture