Delete ONE of the caller's saved strategies. Its BACKTESTS all survive.

Auth + cloak: exactly as PATCH above (404 "Strategy not found" for a stranger, identical to a missing id; a second delete is that same plain 404, never a 500). ?confirm=true is REQUIRED once the strategy has at least one graded run — the 400 says how many runs exist and that they are kept.

A backtest is a self-contained RECEIPT (it carries its own spec_snapshot), so deleting the strategy NULLs vega_backtests.strategy_id and keeps every row. Returns {"deleted": id, "backtests_kept": N}.

Nothing here stops a DEPLOYED bot: the deployment holds its own spec copy, so a bot built from this strategy keeps running exactly as it was. Retire it from the desk if you want it stopped.