Add OKX trading-account USDC auto-swap and lock exit target while in position.

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

backend/app/models/db.py

@@ -34,6 +34,7 @@ CREATE TABLE IF NOT EXISTS groups (
   expiry_ymd TEXT,
   entry_index_px REAL,
   initial_premium REAL DEFAULT 0,
+  exit_target_usdt REAL,
   open_at_ms INTEGER,
   close_at_ms INTEGER,
   close_reason TEXT,
@@ -79,6 +80,7 @@ CREATE TABLE IF NOT EXISTS positions (
   option_entry_px REAL,
   entry_index_px REAL,
   initial_premium REAL DEFAULT 0,
+  exit_target_usdt REAL,
   status TEXT
 );
 
@@ -166,6 +168,8 @@ class Database:
                 ("groups", "funding_usdt", "REAL"),
                 ("groups", "settle_index_px", "REAL"),
                 ("groups", "perp_margin_mode", "TEXT"),
+                ("groups", "exit_target_usdt", "REAL"),
+                ("positions", "exit_target_usdt", "REAL"),
                 ("fills", "exec_mode", "TEXT"),
                 ("fills", "fee_ccy", "TEXT"),
             ):