Build a Chess Game

## Goal
Create a chess game using assets from `Assets/Chess Set` directory.

## Development Plan

### 1. Piece Scripts (`Scripts/Pieces/`)
- Create individual scripts for each chess piece type (Pawn, Rook, Knight, Bishop, Queen, King)
- Each script controls movement rules and logic for that piece type
- Use inheritance with a base `ChessPiece` class for common functionality

### 2. Game Manager Script and Component
- Create `GameManager.cs` to handle core game logic
- Initialize board with pieces in starting positions using:
- Prefabs from `Assets/Chess Set/Prefabs/`
- Scripts from `Scripts/Pieces/`
- Assign the prefabs via the Inspector
- Manage turn system and game state

### 3. Mouse Input Controller Script and Component
- Use the new Unity Input System
- Use raycast to detect piece/square selection
- Visual feedback for selected pieces and valid moves
- Deselection logic (same piece click or empty square)
- Clicking on a valid square moves the piece to that square
- Change piece material to indicate selection
- Add highlight effect to valid move squares

### 4. AI Opponent Script and Component
- Create AI script that makes legal moves
- Implement basic chess strategies
- Include adjustable difficulty levels as script variables
- Use minimax algorithm or similar for move selection
- Use raycasting to detect piece collision.
- The AI should collide with opposing pieces to take them whenever possible.
- IMPORTANT: If a king piece is captured, the game should end immediately.

## Technical Requirements

### Camera Setup
- Position camera x = 0, y = 40, z = -40
- Set camera rotation to 50 degrees for optimal board view

### Piece Positioning
**Important**: 
- Calculate piece positions using board square count and Chess Board Play Surface dimensions
- The Chess Board Play Surface of the board is 48x48 units and there are 64 squares, so each square is 6x6 units.
- **Rotations**:
- All pieces: X-axis = -90° (face upward)
- White pieces: Y-axis = -90°
- Black pieces: Y-axis = 90°
- Chess Board: X-axis = -90° (face upward)
- IMPORTANT: Set Y position = 1 for pawns
- IMPORTANT: Set Y position = 0 for all other pieces
- IMPORTANT: Add box colliders to all pieces with size X = 0.035 Y = 0.03 Z = 0.05

### Best Practices
- Initialize the board and all pieces in the `GameManager` script.
- Use `[SerializeField]` for inspector variables
- Save progress regularly during development
- IMPORTANT: DO not use the Unity Editor to add the board and pieces to the scene.
- IMPORTANT: Add a `BoardClickPlane` GameObject at Y position = 0 and scale of X = 4.8 Y = 1 and Z = 4.8.
- IMPORTANT: Assign a MeshCollider with Mesh value of Plane to the `BoardClickPlane` GameObject.
- IMPORTANT: Add a MeshFilter with Mesh value of Plane to the `BoardClickPlane` GameObject.
- IMPORTANT: Assign the `BoardClickPlane` GameObject a tag called `BoardClickPlane` to detect clicks on the board.
- IMPORTANT: Verify the correct action map is active (usually "UI" for mouse clicks)
- IMPORTANT: Check if Input Actions asset is assigned correctly
- IMPORTANT: Use direct mouse input for reliable clicking - e.g. Vector2 mousePosition = Mouse.current.position.ReadValue();

## Debugging Tips
### 1. Check Unity Console Logs
- Look for `MissingMethodException: Method 'OnClick' not found` errors
- Check for Input System related errors
- Enable debug logging in MouseInputController to trace click detection

### 2. Verify Input System Configuration
- Ensure PlayerInput component is properly configured
- Check if Input Actions asset is assigned correctly
- Verify the correct action map is active (usually "UI" for mouse clicks)

### 3. Test Raycast Detection
Add debug logging to MouseInputController to verify:
- Mouse clicks are detected
- Raycasts hit pieces correctly
- Raycasts hit board/empty squares

## Implementation Order
1. Set up the camera
2. Create base piece class and individual piece scripts
3. Set up GameManager with board initialization and BoardClickPlane
4. Create mouse input controller for piece selection and movement
5. Implement piece positioning and rotation system
6. Create AI opponent with difficulty settings