feat(arena): add deterministic headless RL environments

README.md

@@ -72,6 +72,19 @@ npm install
 npm run dev
 ```
 
+## Headless RL environments
+
+Tera also exports a versioned, renderer-independent Arena contract with four
+deterministic environments: US-101/I-5 driving, Frontier Valley office
+navigation, crow waypoint flight, and California electric-aircraft flight.
+They share the client controllers and office plan, but require no canvas, DOM,
+Three.js scene, network service, or new runtime dependency.
+
+Import them from `@lumbridge/tera/arena`. Seeded train/dev scenarios,
+component rewards, safety terminals, maximum steps, snapshots, checksummed
+traces, exact replay and executable inaction/scripted baseline proofs are
+documented in [ARENA.md](ARENA.md).
+
 ## Using the engine
 
 ```ts
@@ -137,6 +150,7 @@ answer is an RTL-SDR receiver: first-party data with nothing to comply with.
 src/engine/    renderer — terrain, blocks, structures, markers, flights, scene, minimap
 src/cities/    data packs — pure geography, no code
 src/transport/ serializable route packs and renderer-independent simulation
+src/arena/     versioned headless RL contract, scenarios, traces and environments
 src/assets/    original procedural asset library
 src/adapters/  where outside data plugs in
 src/tools/     instruments — god-only, dynamically imported, never statically