Deprecate an HTTP Endpoint

Checklist for deprecating a backend HTTP endpoint. The runtime behavior (warn→error logging, Sentry alerting, response headers) lives in one shared middleware — you only wire it on and supply a date + replacement hint.

The authoritative policy is packages/backend/src/controllers/CLAUDE.md → "Deprecating Endpoints". This skill is the actionable checklist.

Scope — endpoints only

Only HTTP route handlers (TSOA controllers) get the deprecation middleware. Internal service/model methods, type fields, DB columns, and config fields are not endpoints — mark those with a plain @deprecated JSDoc and stop there.

First, check current state

Read the handler before editing. It may already have some of the pieces (@deprecated JSDoc, @Deprecated(), the middleware) — only add what's missing.