Replace status_id with in_progress boolean field

- Remove task_statuses lookup table and StatusID foreign key
- Add InProgress boolean field to Task model
- Add database migration (005_replace_status_with_in_progress)
- Update all handlers, services, and repositories
- Update admin frontend to display in_progress as checkbox/boolean
- Remove Task Statuses tab from admin lookups page
- Update tests to use InProgress instead of StatusID
- Task categorization now uses InProgress for kanban column assignment

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

internal/task/predicates/predicates.go

@@ -60,13 +60,13 @@ func IsArchived(task *models.Task) bool {
 	return task.IsArchived
 }
 
-// IsInProgress returns true if the task has status "In Progress".
+// IsInProgress returns true if the task is marked as in progress.
 //
 // SQL equivalent (in scopes.go ScopeInProgress):
 //
-//	task_taskstatus.name = 'In Progress'
+//	in_progress = true
 func IsInProgress(task *models.Task) bool {
-	return task.Status != nil && task.Status.Name == "In Progress"
+	return task.InProgress
 }
 
 // =============================================================================