Stream a CSV of every fill on the caller org (optionally windowed)

Streaming CSV export of one fill per row. Defaults to all-time fills; pass ISO `since` and/or `until` to narrow. Accepts the same `walletId`/`walletAddress`/`provider` filters as `/v1/me/pnl`. The `sort` param is accepted but IGNORED — rows are always emitted in chronological order. Caps at 50,000 rows post-filter — exceed it and you get a 400 asking you to narrow the window. Includes a `# summary` block at the end with `total_realized,total_unrealized,total_notional,trade_count`. Only `format=csv` is supported today.