Remove legacy scene expansion import package

[yuecideng]

Description

Remove the embodichain.lab.sim.scene_expansion compatibility package so scene expansion has a single import location: embodichain.lab.sim.scene.expansion. Existing users of the removed package must update their imports.

Migrate the contract/source tests to tests/sim/scene/expansion, update the Task Program integration test import, and remove compatibility assertions while retaining the canonical proposal-identity regression. Revise the scene context, routing paths, architecture seed, and design references. The generated architecture snapshot remains pinned to its historical source revision.

Dependencies: none. No linked issue.

Type of change

• Breaking change (existing functionality will not work without user modification)
• Documentation update

Validation

• black . with Black 26.3.1: passed; no formatting changes.
• python docs/scripts/check_api_docs.py: passed, 2594/2594 exports documented.
• python .agents/skills/project-dev-context/scripts/context.py check: passed.
• python -m pytest -q -c /dev/null -p no:cacheprovider --noconftest tests/test_agent_context_map.py tests/test_agent_context_tools.py: 40 passed after rebasing onto current main.
• git diff --check origin/main: passed.
• Changed test syntax, copyright headers, and future annotations: checked.
• python -m pytest -q tests/sim/scene tests/gym/envs/task_program/test_scene_expansion.py: could not collect tests because the local environment lacks dexsim.engine, SciPy, Shapely, and Trimesh. The available gpu-sim environment also lacks DexSim. No simulator qualification is claimed.

Context review: revised scene services/expansion guidance and paths to remove the deleted compatibility contract. General simulation and environment lifecycle guidance remains accurate because their behavior is unchanged.

Checklist

• I have run the black . command to format the code base.
• I reviewed affected documentation and agent context, updated it where needed, or explained why no update was needed.
• Public API changes are reflected in the API docs (python docs/scripts/check_api_docs.py), if applicable.
• Existing tests were migrated to the supported imports; compatibility-only assertions were removed.
• Dependencies reviewed; no changes required.

[greptile-apps]

Confidence Score: 5/5

[Medium impact] The PR appears safe to merge with the explicitly accepted import-path break.

Summary

Removes the legacy embodichain.lab.sim.scene_expansion package and makes embodichain.lab.sim.scene.expansion the single supported import path.

• Scene expansion callers use one import path.

Acknowledged intentional changes:

• yuecideng explicitly states that existing users of the removed package must update their imports.
• yuecideng explicitly leaves the generated architecture snapshot pinned to its historical source revision.

Review checks were static; no simulator tests were run during this review.

_{Reviews (1) · Last reviewed commit: "refactor(scene)!: remove legacy scene ex..." · Reviewed by Greptile}