Add expiry profit estimate and remove chain quick-buy button.

Let users enter a target index in the order panel for estimated expiry P&L, and remove the redundant buy button from the options chain row.

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

lib/options/options_pricing_lib.py

@@ -234,3 +234,26 @@ def format_options_breakeven_line(
     if idx_px is not None and parts:
         return " ".join(parts) + f"（指数{idx_px:.0f}）"
     return " ".join(parts)
+
+
+def estimate_expiry_profit_at_index(
+    *,
+    opt_type: str,
+    strike: float | None,
+    target_idx: float | None,
+    entry_px: float | None,
+    eth_amount: float | None,
+) -> float | None:
+    """到期测算：目标指数价下按内在价值减权利金（每 1 币报价 × 币量）。"""
+    if strike is None or target_idx is None or entry_px is None or eth_amount is None:
+        return None
+    if eth_amount <= 0:
+        return None
+    o = (opt_type or "").upper()
+    if o == "C":
+        intrinsic = max(0.0, float(target_idx) - float(strike))
+    elif o == "P":
+        intrinsic = max(0.0, float(strike) - float(target_idx))
+    else:
+        return None
+    return round((intrinsic - float(entry_px)) * float(eth_amount), 4)