write-backend-documentation

Research a backend codebase end-to-end, propose an approval-gated documentation plan, then generate developer- and LLM-agent-oriented documentation in a consistent house style. Auto-detects language, framework, API surface, data layer, background processing, auth, config, observability, build/deploy, and tests with path:line evidence. A single README lives in the backend root linking into a documentation/ tree; generated docs use UPPERCASE filenames. Existing docs are archived under documentation/archive, never blindly overwritten. Nothing is written before the user approves the plan.