+ [misc] Add unit tests for productZen::getProductList4Kanban() method

- Add getProductList4KanbanTest() method to productZenTest class
- Create test script getproductlist4kanban.php with 7 test steps
- Test empty product list handling
- Test product list filtering and processing
- Test method with various parameter combinations
- All tests pass successfully

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

module/product/test/lib/zen.class.php

@@ -2017,4 +2017,22 @@ class productZenTest extends baseTest
         if(dao::isError()) return dao::getError();
         return $result;
     }
+
+    /**
+     * Test getProductList4Kanban method.
+     *
+     * @param  array $productList
+     * @param  array $planList
+     * @param  array $projectList
+     * @param  array $releaseList
+     * @param  array $projectProduct
+     * @access public
+     * @return array
+     */
+    public function getProductList4KanbanTest(array $productList = array(), array $planList = array(), array $projectList = array(), array $releaseList = array(), array $projectProduct = array())
+    {
+        $result = $this->invokeArgs('getProductList4Kanban', array($productList, $planList, $projectList, $releaseList, $projectProduct));
+        if(dao::isError()) return dao::getError();
+        return $result;
+    }
 }