fix: replace firm-derived name 'John Leppard' with generic 'J. Greenfield'

fix: nginx config context, remove duplicate section, anonymize templates

fix: replace token-format placeholders to avoid secret scanning false positives

docs: update changelog for v3.1.0

docs: add monthly maintenance checklist

docs: add troubleshooting table

docs: add FAQ section

feat: initial OpenClaw setup guide