- reject non-single-symbol feeds with `FeedInitializationError`
- route book and trade data across the correct USD-M endpoints
- accept the first matching L1 or trade quote as feed readiness
- preserve transport and startup-timeout failure context
- cover provider msg schemas and both readiness classes
Prompt-IO: ai/prompt-io/opencode/20260829T175542Z_e09e306a_prompt_io.md
(this patch was generated in some part by `opencode` using `gpt-5.6-sol` (`openai`))