修复币本位实时盈亏闪烁：禁止ETH盈亏与U混加后被两位小数抹成0

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

lib/options/options_positions_lib.py

@@ -144,7 +144,7 @@ def sum_options_net_pnl_usdc(
             continue
         found = True
         total += float(pnl)
-    return round(total, 4) if found else (0.0 if not positions else None)
+    return round(total, 8) if found else (0.0 if not positions else None)
 
 
 def build_display_option_positions(