Covers: topology diagram (Mermaid), OCR memory/VPS sizing table,
dev-vs-prod differences, complete env vars table (all vars verified
against docker-compose.yml and application.yaml, including APP_ADMIN_*
and ALLOWED_PDF_HOSTS gaps not in .env.example), security checklist
before first boot, bootstrap sequence, logs, backup current state vs
planned, common operational tasks, and known limitations with ADR links.
Closes#399
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
