The roadmap capstone: the dungeon is now populated.
- New entity layer: src/entity.rs (Entity { kind, at }, EntityKind {Entrance,
Exit, Treasure, Monster}); Map gains an `entities: Vec<Entity>` overlay field
(serde round-tripped). Entities aren't terrain, so no new Tile and the frozen
viz is untouched.
- EntityPlacer/EntityConfig: places one Entrance (random room), one Exit (the
room farthest from it — a traversal goal), per-room Treasure (treasure_chance)
and Monsters (monster_chance, 1..=max, never in the entrance room). All on
plain Floor only, never two per cell, fully deterministic.
- Handoff via the Blackboard (the designed side channel for non-tile/region/edge
data) under entity::BLACKBOARD_KEY, harvested by Pipeline into Map.entities —
so GenContext's 25 literals stay untouched.
- Renderer draws iconic markers on the final stage: green beacon (entrance),
cyan portal (exit), gold diamond (treasure), crimson eyed-blob (monster), each
with a soft glow. New entities toggle + treasure/monster sliders + readout.
Core: 135 tests green (6 new: one entrance/one exit on distinct floor, entrance
room monster-free, determinism, empty-map, recipe populated-check). clippy
clean. Pipeline is now 9 passes.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
