chore: recover repo after failed OpenClaw update attempt

[seonang]

• revert the failed 2026-04-01 OpenClaw update-attempt changes
• realign GitHub main with the currently known-good Railway runtime baseline
• avoid further speculative deploy loops before a new manual-first update path is validated

Note:

• compared with the known-good pre-update repo baseline, the only remaining difference is a harmless Dockerfile comment block
• no intentional runtime behavior change remains in this recovery branch