Implement Graph Object Oriented Notation (GOON) encoder

Implement the GOON (Graph Object Output Notation) format encoder in the knowledge-graph Rust service and wire it through the Rails integration.

What

GOON is an LLM-optimized text format for knowledge graph query results. It transforms GraphResponse (nodes + edges) into a token-efficient format with progressive disclosure and navigation hints, built on top of TOON encoding.

Key deliverables

  • Rewrite ADR 005 and format spec to reflect TOON-based design
  • Implement GoonFormatter in Rust (currently a 24-line stub)
  • Wire format=llm through REST API (POST /api/v4/orbit/query)
  • Add snapshot tests per query type (search, traversal, neighbors, path finding, aggregation)
  • Update query_graph tool description with GOON format guide

References