The OpenAPI document describes GET /api/v1/user/origins/{id}/browse/{owner}/{name}, and NOT_YET_DESCRIBED is empty

Intent: the last /api/v1 route with no OpenAPI row gets one, so a harness can read an origin repository's landing through OpenAPI alone.

Done:

[ ] A new route file getApiV1UserOriginsIdBrowseOwnerName.ts under src/contract/openapi/routes/, shaped like its siblings (getApiV1UserOriginsIdBrowseOwnerNameBranches.ts). Its summary says who may call it and what it answers, read from the BROWSE landing handler (the repository's facts, branches and readme), and its refusals list the stable error codes the handler and sourceFailure return.
[ ] It is exported from routes/index.ts in that file's sorted order.
[ ] Its line leaves NOT_YET_DESCRIBED in test/openapi-coverage.test.ts. The list is now empty, and the three coverage tests still pass with it empty.
[ ] bun test test/openapi-coverage.test.ts test/openapi.test.ts test/openapi-oa-browse.test.ts passes.

Files: src/contract/openapi/routes/getApiV1UserOriginsIdBrowseOwnerName.ts, src/contract/openapi/routes/index.ts, test/openapi-coverage.test.ts

The OpenAPI document describes GET /api/v1/user/origins/{id}/browse/{owner}/{name}, and NOT_YET_DESCRIBED is empty #6619