Replace hard deletes with deletedAt timestamp flags on all three entities.
Deleting a client or project only sets its own deletedAt; child records are
excluded implicitly by filtering on parent deletedAt in every read query.
Raw SQL statistics queries also filter out soft-deleted parents.
FK ON DELETE CASCADE removed from Project→Client and TimeEntry→Project.
- Add breakMinutes field to TimeEntry model and database migration
- Users can now add break duration (minutes) to time entries
- Break time is subtracted from total tracked duration
- Validation ensures break time cannot exceed total entry duration
- Statistics and client target balance calculations account for breaks
- Frontend UI includes break time input in TimeEntryFormModal
- Duration displays show break time deduction (e.g., '7h (−1h break)')
- Both project/client statistics and weekly balance calculations updated
