v0.29.0

The shared landing page now reads the catalog over the VGI protocol instead of fetching a worker-produced describe.json, which this release deletes.

• Workers pass LandingInfo instead of a describe producer; requires vgi-rpc 0.21.0.
• __describe__ now advertises each unary method's real params schema. It previously advertised an empty schema for all 37, which broke any client that builds its request from the advertised shape.
• Attach options gain required, with validation at catalog_attach.