feat: add OKX options module with dual API, USDT/USDC convert, and docs

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

tests/test_options_pricing.py

@@ -0,0 +1,45 @@
+"""期权定价单测。"""
+from lib.options.options_pricing_lib import (
+    calc_order_size,
+    premium_per_sheet,
+    sheets_from_eth_amount,
+    total_premium,
+)
+
+
+def test_premium_per_sheet():
+    assert abs(premium_per_sheet(15.6, 0.01) - 0.156) < 1e-9
+
+
+def test_total_premium_half_eth():
+    assert abs(total_premium(15.6, 0.5) - 7.8) < 1e-9
+
+
+def test_sheets_from_eth():
+    assert sheets_from_eth_amount(0.5, 0.01) == 50
+
+
+def test_calc_order_size_budget():
+    r = calc_order_size(
+        quote_per_unit=15.6,
+        ct_mult=0.01,
+        min_sz=1,
+        budget_usdc=10,
+        budget_buffer=0.95,
+        budget_cap=10,
+    )
+    assert r["ok"] is True
+    assert r["sheets"] >= 1
+    assert r["total_premium"] <= 10
+
+
+def test_calc_order_size_too_small():
+    r = calc_order_size(
+        quote_per_unit=2000.0,
+        ct_mult=0.01,
+        min_sz=1,
+        budget_usdc=10,
+        budget_buffer=0.95,
+        budget_cap=10,
+    )
+    assert r["ok"] is False