Undo/redo function

[021nirav-blip]

Implement comprehensive undo/redo functionality for Music Blocks

🎯 Summary

This PR implements a complete undo/redo system for Music Blocks that allows users to easily revert and reapply block movements and other actions.

✨ Features Implemented

Core Functionality

• Action-based undo/redo system - Not full snapshots, only stores necessary data
• Keyboard shortcuts - Ctrl+Z (undo) and Ctrl+Y (redo)
• Toolbar buttons - Visual undo/redo buttons with proper state management
• Block position detection - Automatically tracks block movements
• Position restoration - Accurately restores blocks to previous positions

Technical Features

• Prevents recursive saves - Global flag stops infinite undo/redo loops
• EaselJS compatibility - Proper caching and stage updates
• Block visibility management - Z-index handling prevents blocks disappearing
• Error handling - Graceful failure recovery with warnings
• Production-ready code - No debug logs, clean implementation

Integration Points

• Activity integration - Seamless integration with existing Music Blocks architecture
• Block system integration - Works with current block movement system
• UI integration - Toolbar buttons with proper localization
• No breaking changes - Fully backward compatible

🔧 Technical Implementation

Files Modified

• js/undo-redo.js (NEW) - Complete UndoRedoManager class
• js/activity.js (MODIFIED) - Integration, keyboard shortcuts, global flags
• js/block.js (MODIFIED) - Position tracking and state saving
• js/toolbar.js (MODIFIED) - Button rendering and localization
• index.html (MODIFIED) - Undo/redo toolbar buttons

Key Components

• UndoRedoManager class - Manages undo/redo stacks and operations
• Position tracking - Saves initial and final block positions
• State management - Prevents adjustDocks() during undo/redo
• UI updates - Button state reflects stack availability

🎮 User Experience

How It Works

1. Move blocks - System automatically tracks movement start/end positions
2. Press Ctrl+Z - Undo last action, blocks return to original position
3. Press Ctrl+Y - Redo undone action, blocks move forward again
4. Toolbar buttons - Click undo/redo icons for same functionality
5. Visual feedback - Button @walterbender

[github-actions]

❌ Some Jest tests failed. Please check the logs and fix the issues before merging.

Failed Tests:

toolbar.test.js

[021nirav-blip]

having some issues the undo/redo is working but when i apply undo/redo not the whole move to its original place but just the top block i moved rest of it just stay in the same place any idea how to solve it @walterbender @zealot-zew

[walterbender]

How does this mesh with #5481