glm-5.1
3b63d92976
docs: delete metagraph.md, migrate data model into metagraph-module.md
The historical reference doc was exactly the confusing artifact we were
cleaning up. Its unique content (the three-level type system overview
and ASCII diagram) now lives in metagraph-module.md as an introductory
section. Everything else was redundant:
- Schema types → metagraph-module.md (Module entries)
- SchemaBuilder → metagraph-module.md (SchemaBuilder Equivalence section)
- Usage patterns → metagraph-module.md + encrypted-data.md (Module examples)
- Composite identity / attributes storage → sqlite-host.md (table definitions)
- Versioning → schema-evolution.md (thorough treatment)
- Ecosystem context → overview.md (Ecosystem Integration section)
All cross-references updated: AGENTS.md, sqlite-host.md, schema-evolution.md.