feat: add startTrace/stopTrace to control mark capture

Implemented a capture flag in `Ask262Debug` to enable/disable marking.
- Added `_captureEnabled` property and related logic in `mark()`.
- Introduced `startTrace()` and `stopTrace()` methods to toggle capture.
- Updated verification script to start tracing, run tests, stop tracing, and assert that the `Array.prototype.every` section is captured and marked important.

engine262/lib-src/node/verify-ask262-debug.mts

@@ -41,6 +41,7 @@ realm.scope(() => {
   skipDebugger(CreateDataProperty(debugObj, Value('stopImportant'), stopImportant));
 });
 
+ask262Debug.startTrace();
 realm.evaluateScript(`
   // Array.prototype.every - should hit sec-array.prototype.every
   ask262Debug.startImportant();
@@ -50,6 +51,7 @@ realm.evaluateScript(`
   // Proxy creation - should hit sec-proxycreate or similar
   new Proxy({}, {});
 `);
+ask262Debug.stopTrace();
 
 // 3. Verify marks were captured
 console.log('3. Checking marks...');
@@ -61,6 +63,18 @@ if (marks.length === 0) {
   process.exit(1);
 }
 
+// 3a. Assert that Array.prototype.every section is found and marked important
+const everyMark = marks.find((m) => m.sectionIds.some((id) => id.includes('array.prototype.every')));
+if (!everyMark) {
+  console.error('FAIL: sec-array.prototype.every not found in marks');
+  process.exit(1);
+}
+if (!everyMark.important) {
+  console.error('FAIL: sec-array.prototype.every found but not marked as important');
+  process.exit(1);
+}
+console.log('   ✓ Found sec-array.prototype.every (marked as important)\n');
+
 // 4. Show sample marks
 console.log('4. Sample marks:');
 marks.slice(0, 5).forEach((m, i) => {

engine262/src/ask262-debug.mts

@@ -29,6 +29,9 @@ class Ask262Debug {
   /** Whether to mark new entries as important */
   private _important = false;
 
+  /** Whether capture is enabled (controlled by startTrace/stopTrace) */
+  private _captureEnabled = false;
+
   /** Map from deduplication key to index in marks array */
   private _markIndex = new Map<string, number>();
 
@@ -47,11 +50,16 @@ class Ask262Debug {
    * Records a mark for spec section entry during execution.
    * Deduplicates based on (sectionIds, file, line) combination.
    * If duplicate found, merges important flags (OR logic).
+   * Only captures if tracing is enabled (via startTrace()).
    * @param sectionIds - Array of ECMAScript spec section IDs
    * @param file - Relative file path from engine262/src/
    * @param line - Line number in source file (1-indexed)
    */
   mark(sectionIds: string[], file: string, line: number) {
+    if (!this._captureEnabled) {
+      return;
+    }
+
     const key = this._makeKey(sectionIds, file, line);
     const existingIndex = this._markIndex.get(key);
 
@@ -75,6 +83,22 @@ class Ask262Debug {
     this.marks.push(newMark);
   }
 
+  /**
+   * Enables capture of marks during execution.
+   * Marks will be recorded until stopTrace() is called.
+   */
+  startTrace() {
+    this._captureEnabled = true;
+  }
+
+  /**
+   * Disables capture of marks during execution.
+   * Marks will be ignored until startTrace() is called again.
+   */
+  stopTrace() {
+    this._captureEnabled = false;
+  }
+
   /**
    * Marks subsequent mark() calls as important.
    * Used to annotate interesting execution phases.