test(invoice): implement integration tests for invoice behaviors
Adds comprehensive integration tests covering:
- Invoice list filtering (vendor, account, date range, due date, amount, import status, scheduled payments, unresolved, location)
- Invoice list sorting (date, invoice number, due date, total, outstanding balance, vendor, client, location)
- Invoice list pagination (default 25, custom per-page)
- Selection behaviors (select all filtered)
- Permission gates (GraphQL layer behavior)
- Lock date behaviors (edit, void, unvoid, undo autopay, bulk operations)
- Single/Bulk void with payment exclusions
- Bulk edit with lock date exclusions
- Credit payment (net zero, multiple vendors blocked, positive balance blocked)
- Import validation (missing fields, unmatchable vendors, no client access)
- Import approve/disapprove
- Legacy route redirects
Updates docs/testing/behaviors/invoice.md with 76 completed behavior markers.
57 tests, 99 assertions, all passing.
Bryce
1a48abdd7c