Use `Context.wait_for_result()` directly at the nine remaining
call sites, including the debugger's root stdio-lock handshake.
Preserve `hide_tb=False` in the payload-spec test and keep the
outcome-renaming TODO beside the supported API.
Update the API removal note, ctx-specific comments and drain
diagnostics, and include the API-removal Prompt-IO record.
Prompt-IO: ai/prompt-io/opencode/20260922_context_result_removal.md
(this patch was generated in some part by `opencode`
using `gpt-6-astra` (`openai`))
Gud Boi