Document chunks not stored in vector store (#665)

- Schema - ChunkEmbeddings now uses chunk_id: str instead of chunk: bytes
- Schema - DocumentEmbeddingsResponse now returns chunk_ids: list[str]
  instead of chunks
- Translators - Updated to serialize/deserialize chunk_id
- Clients - DocumentEmbeddingsClient.query() returns chunk_ids
- SDK/API - flow.py, socket_client.py, bulk_client.py updated
- Document embeddings service - Stores chunk_id (document ID) instead
  of chunk text
- Storage writers - Qdrant, Milvus, Pinecone store chunk_id in payload
- Query services - Return chunk_id from vector store searches
- Gateway dispatchers - Serialize chunk_id in API responses
- Document RAG - Added librarian client to fetch chunk content from
  Garage using chunk_ids
- CLI tools - Updated all three tools:
  - invoke_document_embeddings.py - displays chunk_ids, removed
    max_chunk_length
  - save_doc_embeds.py - exports chunk_id
  - load_doc_embeds.py - imports chunk_id

trustgraph-base/trustgraph/api/socket_client.py

@@ -682,7 +682,7 @@ class SocketFlowInstance:
             **kwargs: Additional parameters passed to the service
 
         Returns:
-            dict: Query results with similar document chunks
+            dict: Query results with chunk_ids of matching document chunks
 
         Example:
             ```python
@@ -695,6 +695,7 @@ class SocketFlowInstance:
                 collection="research-papers",
                 limit=5
             )
+            # results contains {"chunk_ids": ["doc1/p0/c0", ...]}
             ```
         """
         # First convert text to embeddings vectors