test(extractor): verify exported arrow function funcStack tracking in extractSpreadForOfWalk (#1354)

Add regression tests confirming that `export const f = (arr) => { for (const x of arr) x(); }`
correctly pushes `f` onto the funcStack so for-of bindings record the right enclosing caller.
The recursive walk visits `variable_declarator` regardless of whether it is nested under a plain
`lexical_declaration` or an `export_statement`, so the gap reported in the PR #1331 review was
already closed by commit a6c5d2d. These tests document and gate that behavior.

Closes #1354

Author: carlos-alm

tests/parsers/javascript.test.ts

@@ -908,4 +908,27 @@ describe('JavaScript parser', () => {
       );
     });
   });
+
+  describe('Phase 8.3e: extractSpreadForOfWalk — exported arrow function funcStack (#1354)', () => {
+    it('tracks plain const arrow function on funcStack for for-of loop', () => {
+      const symbols = parseJS(`const f = (arr) => { for (const x of arr) x(); };`);
+      expect(symbols.forOfBindings).toContainEqual(
+        expect.objectContaining({ enclosingFunc: 'f' }),
+      );
+    });
+
+    it('tracks exported const arrow function on funcStack for for-of loop', () => {
+      const symbols = parseJS(`export const f = (arr) => { for (const x of arr) x(); };`);
+      expect(symbols.forOfBindings).toContainEqual(
+        expect.objectContaining({ enclosingFunc: 'f' }),
+      );
+    });
+
+    it('records correct varName and sourceName for exported arrow for-of', () => {
+      const symbols = parseJS(`export const process = (items) => { for (const cb of items) cb(); };`);
+      expect(symbols.forOfBindings).toContainEqual(
+        expect.objectContaining({ varName: 'cb', sourceName: 'items', enclosingFunc: 'process' }),
+      );
+    });
+  });
 });