59b0ea98c8
When a turn ends abnormally after substantive tool calls (empty content after retries, a partial/truncated stream, exhausted retries, or an iteration/budget limit), the CLI/TUI response area was left blank or showed only a fragment (e.g. "The") with no consolidated reason. The internal turn_exit_reason values (empty_response_exhausted, partial_stream_recovery, etc.) were never surfaced to the user. Add a turn-completion explainer that mirrors the existing file-mutation verifier footer: at turn end, map an abnormal turn_exit_reason to a short, actionable message and either replace the bare "(empty)" sentinel or append the reason after a partial fragment. Normal text_response exits (e.g. a terse "Done.") stay quiet. Gated by display.turn_completion_explainer (default on) with HERMES_TURN_COMPLETION_EXPLAINER env override, matching the file-mutation verifier seam. Closes #34452