MUL-5240
cursor-agent's stream-json never populates total_cost_usd or a per-step
cost — the result event's usage object carries token counts only. Both
fields were speculatively copied from Claude Code's schema in the original
Cursor runtime PR (#1057) and were never read. Verified against the real
CLI (2026.07.20, stream-json and json) plus Cursor's CLI docs.
Remove the two dead fields and document that Cursor spend stays estimated
from the static rate table (no authoritative per-turn cost to carry, unlike
Grok). No behavior change.
Co-authored-by: Bohan-J <bohan@devv.ai>
Co-authored-by: multica-agent <github@multica.ai>
bce0c05856