Occupied tiles now block movement through World::blocked, the one predicate
the sim and the pathfinder share. Entities carry an EntityKind so the sim
knows which ones to think for; Sim::think gives each NPC a random king move
one window in four. Intents execute in id order so contested tiles resolve
deterministically.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Move chunk, entity, world, map, sim and load_world into a new sim library
crate together with the game rules from shared (player_action, action_delta,
delta_action, step_allowed, tile_collidable, tick constants). shared keeps
only the wire types and re-exports the rules, so server and client compile
unchanged. First step toward a local single-player build.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>