ObjectBox 4.0 Vector Search

• ObjectBox now supports vector search ("vector database") to enable efficient similarity searches.
  This is particularly useful for AI/ML/RAG applications, e.g. image, audio, or text similarity.
  Other use cases include semantic search or recommendation engines.
  See https://docs.objectbox.io/ann-vector-search for details.
• Adjusting the version number to match the core version (4.0); we will be aligning on major versions from now on.