List valuation widget keys

Lists the organization's publishable valuation widget keys for the key's environment when the authenticated client has valuations.embed_keys.read, newest first, with each key's registered origins and status. External URL: /v1/valuations/embed-keys. Current Next.js implementation path: /api/platform/v1/valuations/embed-keys. This read-only route does not require Idempotency-Key. A widget key is publishable, not a secret: it ships in the partner page and works only on the free public valuation routes, from its registered origins, with a cap of 2,000 estimates a day per key. It never authenticates this API.