refactor: convert relative imports to package imports

Replace all relative imports (../../) with package imports
(package:tatlock_ui/) across 29 files for cleaner, more
maintainable import paths.

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

lib/features/control_room/stacks/data/models/stack_model.dart

@@ -1,6 +1,5 @@
 import 'package:freezed_annotation/freezed_annotation.dart';
-
-import '../../domain/entities/stack.dart';
+import 'package:tatlock_ui/features/control_room/stacks/domain/entities/stack.dart';
 
 part 'stack_model.freezed.dart';
 part 'stack_model.g.dart';