Deduct open position margin from recommend max lots.

Recalculate tradable symbol budgets from remaining margin after CTP usage and refresh the table on position updates.

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

install_trading.py

@@ -1578,6 +1578,12 @@ def install_trading(app, *, login_required, require_nav, get_db, get_setting, se
             try:
                 payload = _refresh_trading_live_snapshot(fast=fast)
                 position_hub.broadcast("positions", payload)
+                conn = get_db()
+                try:
+                    rec = _recommend_payload(conn)
+                    recommend_hub.broadcast("recommend", {"ok": True, **rec})
+                finally:
+                    conn.close()
             except Exception as exc:
                 logger.debug("push position snapshot: %s", exc)