- Fix TestCollectionsBulkOperations/BulkAddBooks_SingleOperation failure
- Each subtest was creating "Test Collection" with same name
- Collections table has UNIQUE(user_id, name) constraint causing 500 errors
- Made collection names unique by adding test name suffix:
- Test Collection - InvalidBookID
- Test Collection - SingleOperation
- Test Collection - MultipleBooksSingleCollection
- Test Collection 1 - MultipleCollections
- Test Collection 2 - MultipleCollections
- Test Collection - DuplicateBooks
This preserves test data for manual API testing with Bruno while
ensuring test isolation and preventing unique constraint violations.