This commit increases the test coverage of the `internal/app/work` package from 73.1% to over 80% by adding new tests and fixing a bug discovered during testing.
The following changes were made:
- Added tests for the `ListByCollectionID` query in `queries_test.go`.
- Added a unit test for the `NewService` constructor in `service_test.go`.
- Added tests for authorization, unauthorized access, and other edge cases in the `UpdateWork`, `DeleteWork`, and `MergeWork` commands in `commands_test.go`.
- Fixed a bug in the `mergeWorkStats` function where it was not correctly creating stats for a target work that had no prior stats. This was discovered and fixed as part of writing the new tests.
- Updated the `analytics.Service` interface and its mock implementation to support the bug fix.
