[checkpoint] Restore anyswe_agent sandboxes #3276

Parent

Child of #3222 and #3024. Depends on #3275.

Runtime state

responses_api_agents/anyswe_agent/app.py owns the selected CLI harness, repository/workspace modifications, patch/trajectory, and mounted result directory inside a sandbox.

Adapter requirements

Persist the logical execution-to-runtime mapping, provider/version and physical generation, sandbox snapshot/reference, image/spec and mount fingerprints, agent or verifier cursor, and result-manifest identity. Rebind a replacement runtime atomically and fence the old handle. Never claim that a filesystem-only copy restores unsupported live process state.

Acceptance criteria

• Repository changes, patch and trajectory survive, and the selected harness resumes without rebuilding or re-running completed actions.
• Mutate runtime state, commit, replace both application and runtime process where supported, restore, and compare the next operation/result.
• Stale handles and delayed old-runtime results are rejected.
• Partial restore activates no execution mapping.
• Duplicate retirement and failed-provider cleanup release the restored runtime exactly once.