Release notes: 2026-05-27 — sim-3-env-pool-stub¶

Status: Ready for review
Repo: li-langverse/lic
PR: (pending)
PH / REQ: PH-SIM SIM-2, PH-SIM SIM-3
Author: agent

Summary (one sentence)¶

li-sim gains SIM-2 replay metadata and SIM-3 EnvPoolStub/env_pool_stub_step so RL profile ticks batch sim_step with obs/reward contract stubs.

Agent continuation (required)¶

1. Read: packages/li-sim/src/lib.li, docs/game-dev/studio-full-implementation-plan.md § WP-SIM-03.
2. Run: lic check packages/li-sim/li-tests/smoke/env_pool_stub.li; wire studio_sim_step_hook sim_rl branch if not merged from sibling vertical PR.
3. Then: promote persistent EnvPool in li-ml-rl re-exporting sim types; add env_pool_step_contract.li composable test.
4. Blocked on: async multi-env sampling (PH-ML) — none for this stub merge.

Changed (specific)¶

Not changed (scope fence)¶

• li-studio studio_sim_step_hook sim_rl branch — not in this PR (sibling vertical batch).
• li-ml-rl package scaffold — not created; types live in li-sim per SIM-3 deepen task.
• Physics kernels, tier-2 benches, MCP — not touched.

Breaking changes¶

None — additive fields on SimSessionStub with defaults in sim_session_stub_default().

Security¶

N/A — deterministic stub counters only; no IO or trusted surface.

Performance¶

N/A — composable stub; no bench row.

Downstream¶

CHANGELOG entry (paste into Unreleased)¶

### Added
- **PH-SIM SIM-3 RL env pool stub** — `EnvPoolStub`, `env_pool_stub_step`, `sim_rl_tick_stub` in `packages/li-sim`; SIM-2 replay on `SimSessionStub`; smoke `env_pool_stub.li`.