docs: merge deployment.md into README, delete deployment files
- Move operational content (env var reference, multi-instance prerequisites,
troubleshooting, cron-drain, CF Dashboard Git integration, BACKEND_ORIGINS_JSON
format, security checklist) into README and README.zh-CN
- Delete docs/deployment.md and docs/deployment.zh-CN.md
- Update 5 validator DOCS lists to remove deployment entries
- Update charter §7 doc boundary table, AGENTS §2.5 line-anchor exception
- Fix cross-doc references in design/reference/opengaps/retired/worker READMEs
- Fix cron-drain.sh header comment reference (deployment.md §6.3 → README §3.10)
- GATE-DOCS 6/6 PASS (55 anchors / 441 sec-refs / 699 path-refs, 0 errors)
anonsaber
7aedcd4145