These hooks existed only to serve the sandbox_profile harness, which was deleted in c8563df9f; they had zero product callers. Revert the backup side to 8e2ec2632. This removes run_restic_json_records and ResticJsonRecordsResult, and restores run_restic to its pre-arc single-subprocess signature and ResticResult to its 5-field shape. It also deletes solstone/think/json_codec.py, whose sole importer was backup/runner.py. state.get_daily_key, readiness.inspect_restic_ready, s3_wipe.list_prefix_contents, and rclone_install.check_rclone_ready go with the removed harness surface. readiness.check_restic_ready keeps its real product caller at backup/install.py:216, which passes no version_timeout, so that call site needed no edit. The five backup test files were sandbox-arc-only since baseline, so reverting them restores the pre-existing assertions byte-identical. The design doc no longer documents the removed runner API. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>