Ships #227: the lane-B public seam (workos_provider_from_env — unblocks
dna-cloud's /consumer, which 404'd since the monolith cutover), the readable
round-trip-safe YAML doc writer, and the debranded scope defaults.

Work-Item: Story/s-serving-seams-for-apps

Co-authored-by: Jefferson Barnabé <3090620+ruinosus@users.noreply.github.com>
Co-authored-by: dna-sdlc[bot] <302582850+dna-sdlc[bot]@users.noreply.github.com>