* Rework metadata structure in processing messages to be a subgraph
* Add subgraph creation for tg-load-pdf and tg-load-text based on command-line passing of doc attributes
* Document metadata is added to knowledge graph with subjectOf linkage to extracted entities
* Update schema defs for source -> metadata
* Migrate to use metadata part of schema, also add metadata to triples & vecs
* Add user/collection metadata to query
* Use user/collection in RAG
* Write and query working on triples
