[jonwillits]

Builds stage c3a of docs/specs/WORLD_PHASE_C.md: location fluents (pair_fluents.locations above 0 when the world has places, labeled after the pair fluents between entities, with the fixed profile general, functional, and total, from entities to places, and a null initial rate in their symbol); initial places drawn from the new stream world:habitats, after world:pair_conditions, with the habitat weights (1 + a(x, q)) ^ places.habitat_strength, written as columns of entities.csv; the runtime over location fluents (PAIRFL.k(agent, patient) and SOMEOF of a place in place event types, SAME on a location fluent in event types between entities, never SOME of an entity; the total functional replacement in apply; the profile check; a move's row and a place's column as the keys of non-interference); place event types made performable as moves and acts by an event file's place_event_types entries (the compiled move literal and the act literal with their origins, explicit requirements over entity and place literals, the rules and errors that name the file and the entry, the invariant checker check_place_dynamics); places in episodes (scene.extra_places, scene.places, scene.initial_location, the redraw of places with the habitat weights, every new draw after every existing draw) and in histories (places, initial_places, a move's two changes, replay with every profile checked); the three scene keys in both readers; the brute-force evaluator over location pairs and the fixture format's initial_places; the hand world extended with two places, a location fluent, three place event types, and a SAME event type, with the hand fixtures 38 to 44 (items 5 to 9, 11, and 15 of the specification) and the 37 earlier hand fixtures regenerated with no state, event, or earlier legality verdict changed; the chain example data/world/events/place_chain_example.yaml with data/world/tiny_place_chain.yaml, in the snapshot; and the documents (WM.64 and the c3a/c3b split in the specification, the as-built notes, the guides, the fixtures README, CLAUDE.md, DECISIONS.md with WM.64 and WM.E290 to WM.E306).

Every configuration of data/ except the chain example's gives the world of stage c2b byte for byte apart from config.yaml (the seed of world:habitats): no snapshot figure or baseline moved, and the snapshot gained the tiny_place_chain world's figures. The corpus is unchanged and refuses every world with pair fluents, location fluents included.

Proposal: docs/proposals/2026-10-21-world-stage-c3a-decisions.md.

Co-Authored-By: Claude Fable 5.1 noreply@anthropic.com