TEMPL API
REST endpoints + OAuth callbacks for TEMPL services.
Planned routes
GET /shopify/auth— TEMPL App (storefront) installGET /shopify/auth/dev-ai— TEMPL Dev AI installGET /shopify/auth/stew— STEW App install
Versioning: unversioned paths serve the latest; /v1/, /v2/ pin a specific version (re-exports of the relevant implementation, never parallel codepaths).