Every read tool (entity_context, state_at, was_true_at, ancestors_of,
descendants_of, lineage_of, recall_images, search_images_by_caption,
register_image) now accepts an optional world_id parameter, defaulting
to 'default' so v1 callers see no change.
* Neo4j: every Person/Faction/Location/Item/Event/Lineage/Image node
carries a world_id string property. seed.py backfills existing nodes
to 'default' and writes a second minimal world 'arda_greyscale'
(2 people, 1 faction, 1 location, 4 relations, 1 event, 1 era).
* Cypher: every MATCH in the world/lineage/images plugins filters by
world_id on the right node type.
* New admin tool list_worlds() — runs
MATCH (n) WHERE n.world_id IS NOT NULL RETURN DISTINCT n.world_id
to expose the namespace.
* Postgres image_manifest gains a world_id column (init.sql).
* 4 placeholder images generated for the greyscale world (portraits of
Mael and Sira, Ashen Hall, the Ashen Oath).
* test.sh now calls every tool with world_id='default' to verify v1
behaviour, plus a new section 12 that calls list_worlds().
* tests/test_multi_world.py: 14 pytest cases covering list_worlds,
entity_context/world isolation, was_true_at, state_at, lineage
filter, image recall isolation, and the image_manifest schema.
Verification:
pytest tests/test_multi_world.py 14/14 pass
bash test.sh 12/12 sections green,
MinIO image bytes flow 200 OK
list_worlds() returns [{arda_greyscale}, {default}]
