refactor: standardize variable naming and file formatting

- Rename Quantity to quantity in BomItem for consistent naming convention
- Update references in MainModule to use lowercase quantity
- Add newlines at end of files for consistency
- Update vba_metadata.json with new source path and document module

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

VBA/DocumentModules/Sheet9.cls

@@ -0,0 +1,4 @@
+Private Sub CommandButton1_Click()
+    Call ProcessProductModels
+    Call ProcessOrdersToBIP
+End Sub