Development record

The session chapter's blueprint section names two files, render.yaml and .abcd/relay/Dockerfile (.abcd/development/brief/04-surfaces/37-session.md:118-129), and its page section relies on .abcd/relay/relays.json (line 153) without saying what writes it. `abcd session blueprint --relay-origin` and `abcd session setup --relay-origin` also write relays.json, and `abcd session setup` writes .abcd/relay/github-app.json. Those writes are stated only in the verb's help and commands/session.md.