Fix: Support Kalshi v2 fixed-point fill fields

lib/live/engine.js

@@ -124,11 +124,6 @@ export class LiveEngine {
     }
   }
 
-  /**
-   * Determine the best executable price from the orderbook.
-   * For buying yes: best ask = 100 - best_no_bid (or lowest yes offer)
-   * For buying no: best ask = 100 - best_yes_bid (or lowest no offer)
-   */
   _getBestAskFromOrderbook(side, orderbook) {
     if (!orderbook) return null;
 
@@ -146,6 +141,20 @@ export class LiveEngine {
     return null;
   }
 
+  _getFillCount(order) {
+    if (!order) return 0;
+    const fp = order.taker_fill_count_fp ?? order.fill_count_fp;
+    if (fp != null) return Math.round(parseFloat(fp));
+    return order.taker_fill_count ?? order.fill_count ?? 0;
+  }
+
+  _getFillCostCents(order) {
+    if (!order) return 0;
+    const dollars = order.taker_fill_cost_dollars ?? order.fill_cost_dollars;
+    if (dollars != null) return Math.round(parseFloat(dollars) * 100);
+    return order.taker_fill_cost ?? order.fill_cost ?? 0;
+  }
+
   /**
    * Verify an order's actual fill status by polling Kalshi.
    * IOC responses can report 0 fills even when fills happened async.
@@ -158,8 +167,8 @@ export class LiveEngine {
         const order = data?.order;
         if (!order) continue;
 
-        const fillCount = order.taker_fill_count || order.fill_count || 0;
-        const fillCost = order.taker_fill_cost || order.fill_cost || 0;
+        const fillCount = this._getFillCount(order);
+        const fillCost = this._getFillCostCents(order);
         const status = (order.status || '').toLowerCase();
         const isFinal = ['canceled', 'cancelled', 'executed', 'filled', 'closed'].includes(status);
 
@@ -255,8 +264,8 @@ export class LiveEngine {
         return null;
       }
 
-      let fillCount = order.taker_fill_count || 0;
-      let fillCost = order.taker_fill_cost || 0;
+      let fillCount = this._getFillCount(order);
+      let fillCost = this._getFillCostCents(order);
       let status = (order.status || '').toLowerCase();
 
       // If immediate response says 0 fills, verify with Kalshi to catch async fills