ELCC-94: Add Per-Center Per-Month Building Expense Customization

[klondikemarlen]

Fixes https://yg-hpw.atlassian.net/browse/ELCC-94

Context

End users reported that building expenses are fairly informal and need to be customized on a per-month, per-center basis. The existing interface only supported bulk management at the category level, with no way to add, remove, or individually adjust expenses for specific centres and fiscal periods.

Implementation

1. Rename the building expense category foreign key to categoryId and update the related API, model, serializer, and migration layers.
2. Add inline monthly worksheet controls to create, edit, and delete building expenses directly in the Building Expenses section.
3. Expose building expense policy actions through the API so the worksheet can show the right actions per row.
4. Scope building expense category selection by funding region and exclude categories already used for the same centre and fiscal period.
5. Add bulk-forward creation services so new building expense categories and optionally new building expenses can be copied into later fiscal periods.
6. Allow building expenses to be edited across fiscal periods, while still limiting subsidy rate edits to system admins.
7. Tighten supporting backend and test infrastructure, including the BaseModel.withScope typing fix needed for scoped findEach calls.

Screenshots

New Building Expense table with add/remove options.
http://localhost:8080/child-care-centres/1/2025-26/worksheets/march

Building expense form open.
http://localhost:8080/child-care-centres/1/2025-26/worksheets/march?showBuildingExpenseCreateForm=true

Category selector open with no category found and a link to create a category for admins.
http://localhost:8080/child-care-centres/1/2025-26/worksheets/march?showBuildingExpenseCreateForm=true

Expense category creation page with the apply-forward option.
http://localhost:8080/administration/building-expense-categories/new

Testing Instructions

1. Run the test suite via dev test.
2. Boot the app via dev up.
3. Log in to the app at http://localhost:8080.

Test Case 1: User can add a building expense from a monthly worksheet

4. Open any child care centre worksheet and click any month tab to load the Monthly Worksheet page.
5. Scroll to the Building Expenses section.
6. Verify the table displays an Actions column.
7. Click the Add Building Expense button.
8. In the Add Building Expense form, click the Category autocomplete.
9. Verify the autocomplete hint reads Search for a building expense category..
10. Select a category and enter values in Estimated Cost and Actual Cost.
11. Optionally enter text in Notes.
12. Leave Apply to current and future fiscal periods for this centre unchecked.
13. Click Create.
14. Verify the success message Building expense created successfully appears.
15. Verify the new row appears in the Building Expenses table.

Test Case 2: User can apply a building expense to later fiscal periods

16. In the same Monthly Worksheet page, click Add Building Expense again.
17. Select a different value in Category.
18. Enter values in Estimated Cost and Actual Cost.
19. Check Apply to current and future fiscal periods for this centre.
20. Click Create.
21. Verify the success message Building expense created successfully appears.
22. Click a later month tab in the worksheet.
23. Verify the newly created building expense appears in that later month's Building Expenses table.

Test Case 3: User can edit and delete a building expense

24. On any worksheet month that has building expenses, edit Estimated Cost, Actual Cost, or Notes in the Building Expenses table.
25. Verify the success message Building expense saved! appears.
26. Refresh the page.
27. Verify the edited values persist.
28. Click Delete on a building expense row.
29. In the confirmation prompt, confirm the deletion.
30. Verify the success message Building expense deleted! appears.
31. Verify the deleted row is removed from the Building Expenses table.

Test Case 4: Past months remain editable

32. Navigate to a past worksheet month by clicking an earlier month tab.
33. Verify the Building Expenses section still shows the Add Building Expense button.
34. Verify the table still shows the Actions column.
35. Edit a value in an existing building expense row.
36. Verify the success message Building expense saved! appears.
37. Delete a building expense row.
38. Verify the success message Building expense deleted! appears.

Test Case 5: System admins can manage subsidy rate and create categories

39. Log in as a system admin.
40. Open any Monthly Worksheet page with building expenses.
41. Edit the Subsidy Rate / $ field for a building expense row.
42. Verify the success message Building expense saved! appears.
43. Open the profile menu and navigate to Administration → Building Expense Categories.
44. Click New Building Expense Category.
45. Fill in Funding Region, Category Name, and **Subsidy Rate ***.
46. Optionally check Apply to all current and future centre funding periods.
47. Click Create Building Expense Category.
48. Verify the success message Building expense category created successfully! appears.
49. Return to a Monthly Worksheet page for a centre in the same funding region.
50. Click Add Building Expense.
51. Verify the new category can be selected from Category.

Test Case 6: Empty category search offers the admin create flow

52. While logged in as a system admin, open Add Building Expense on a Monthly Worksheet page.
53. In Category, search for a value that does not exist.
54. Verify the empty state shows Can't find what you're looking for?.
55. Verify the Create Category button appears in that empty state.
56. Click Create Category.
57. Verify the app navigates to Administration → Building Expense Categories → New Building Expense Category.