币本位持仓卡权利金/回收/门控改为按ETH/BTC展示，避免误标USDC与两位小数抹零

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/options/options_register.py

@@ -533,7 +533,21 @@ def register_options_routes(app: Flask, cfg: dict[str, Any]) -> None:
         if mode == "close_preview":
             paid = _open_premium_paid(cfg, inst_id)
             target = sheet_count if sheet_count is not None else 0
-            return jsonify(_attach_close_preview(cfg, ex, {**q, "pos": target, "premium_paid": paid}, sheets=target, premium_paid=paid))
+            from lib.options.options_margin_mode_lib import margin_mode_from_inst_id, premium_ccy_for_mode
+
+            row_mode = margin_mode_from_inst_id(inst_id)
+            prem_ccy = premium_ccy_for_mode(row_mode, (inst_id.split("-")[0] if inst_id else "ETH"))
+            preview_row = {
+                **q,
+                "pos": target,
+                "premium_paid": paid,
+                "margin_mode": row_mode,
+                "premium_ccy": prem_ccy,
+            }
+            out = _attach_close_preview(cfg, ex, preview_row, sheets=target, premium_paid=paid)
+            out["options_margin_mode"] = row_mode
+            out["premium_ccy"] = prem_ccy
+            return jsonify(out)
         mode, mode_note = _normalize_size_mode(mode)
 
         # 币本位:报价预览走 USDT 预算→估币→张数,禁止再查 USDC