Add section organization to 08_dataloader module: Add DEVELOPMENT section header

- Insert ## 🔧 DEVELOPMENT header before first test function
- Organizes module according to educational structure guidelines
- Maintains all existing functionality and test execution
- Improves readability and navigation for educational use

modules/source/08_dataloader/dataloader_dev.py

@@ -963,6 +963,11 @@ except Exception as e:
 
 print("📈 Final Progress: Complete data pipeline ready for production ML!")
 
+# %% [markdown]
+"""
+## 🔧 DEVELOPMENT
+"""
+
 # %%
 def test_unit_dataset_interface():
     """Unit test for the Dataset abstract interface implementation."""