refactor: add fuel efficiency tracking to Turtle class

server/Turtle.js

@@ -98,6 +98,11 @@ export class Turtle extends EventEmitter {
     this._messageIndex = 0;
     this._lastPromise = Promise.resolve(); // Promise chain for sequential exec
 
+    // Fuel efficiency tracking
+    this._stepsSinceLastRefuel = 0;
+    this._totalSteps = 0;
+    this._totalFuelUsed = 0;
+
     // Connection tracking
     this.connected = false;
     this.lastUpdate = Date.now();
@@ -447,6 +452,8 @@ export class Turtle extends EventEmitter {
     if (result === true || (Array.isArray(result) && result[0] === true)) {
       this.updatePositionForward();
       this._deleteBlockAtPosition(this._position);
+      this._stepsSinceLastRefuel++;
+      this._totalSteps++;
     }
     return result;
   }