cocoanut 0.2.1

# Code Improvements Summary

This document summarizes the improvements made to the Cocoanut codebase.

## Overview

The improvements focus on:
1. **Type Safety** - Stronger type guarantees
2. **Documentation** - Better API docs and guides
3. **Developer Experience** - Better tooling and processes
4. **Code Quality** - Better organization and error handling

## Changes Made

### 1. Type Safety Improvements

#### Added `CallbackId` Type
- **File**: `src/event.rs`
- **Change**: Introduced type-safe wrapper for callback IDs
- **Benefit**: Prevents accidental mixing of callback IDs with other integers

```rust
pub struct CallbackId(pub usize);

impl CallbackId {
    pub fn new(id: usize) -> Self;
    pub fn as_usize(&self) -> usize;
}
```

### 2. Enhanced View Styling

#### New Style Modifiers
- **File**: `src/view.rs`
- **Added**:
  - `.margin(f64)` - Set margin around views
  - `.italic()` - Make text italic
  - `.alignment(Alignment)` - Set text/content alignment

#### New `Alignment` Enum
```rust
pub enum Alignment {
    Leading,   // Left-aligned
    Center,    // Centered
    Trailing,  // Right-aligned
}
```

### 3. Improved Error Handling

#### Enhanced Error Types
- **File**: `src/error.rs`
- **Added**: `Rendering(String)` error variant
- **Improved**: All error variants now have detailed documentation

### 4. Better Documentation

#### API Documentation
- **Files**: `src/view.rs`, `src/app.rs`, `src/state.rs`
- **Added**: Comprehensive doc comments with examples
- **Organized**: Constructor methods into clear sections:
  - Layout Containers
  - Text Views
  - Form Controls
  - (etc.)

#### Code Organization
- Added visual section separators in constructors
- Improved readability with better comments

### 5. Developer Guides

#### CONTRIBUTING.md
- **File**: `CONTRIBUTING.md`
- **Content**:
  - Project philosophy (KISS, DRY, SoC)
  - Development setup instructions
  - How to add new view types
  - Style guidelines
  - PR process
  - Commit message format

### 6. CI/CD Infrastructure

#### GitHub Actions Workflow
- **File**: `.github/workflows/ci.yml`
- **Features**:
  - Automated testing on push/PR
  - Formatting checks (`cargo fmt`)
  - Linting (`cargo clippy`)
  - Documentation building
  - Example building
  - Caching for faster builds

### 7. Quality Tooling

#### Quality Check Script
- **File**: `scripts/quality-check.sh`
- **Checks**:
  - Code formatting
  - Linting
  - Tests
  - Documentation
  - Examples
  - Line count tracking

### 8. State Management Enhancements

#### New `State<T>` Methods
- **File**: `src/state.rs`
- **Added**:
  - `.modify(f)` - Convenient alias for `.update()`
  - `.map(f)` - Map over the current value

```rust
let state = State::new(42);
let doubled = state.map(|v| v * 2);  // Returns 84
```

### 9. Changelog

#### CHANGELOG.md
- **File**: `CHANGELOG.md`
- **Purpose**: Track all changes following Keep a Changelog format
- **Sections**: Added, Changed, Fixed, Removed

## Impact

### Code Quality Metrics
- **No compiler errors**: ✅
- **No compiler warnings**: ✅
- **Type safety**: Improved with `CallbackId`
- **Documentation coverage**: Significantly increased
- **CI/CD**: Automated testing and checks

### Developer Experience
- **Contributing guide**: Makes it easy for new contributors
- **Quality script**: One command to check everything
- **CI/CD**: Automated quality gates
- **Better docs**: Easier to understand the API

### Maintainability
- **Error handling**: More descriptive error messages
- **Code organization**: Better section separation
- **Documentation**: Self-documenting code
- **Changelog**: Track changes over time

## Future Recommendations

### Short Term
1. Add more unit tests for edge cases
2. Add integration tests
3. Document internal architecture patterns
4. Add benchmarks for performance tracking

### Medium Term
1. Implement Auto Layout constraints (from TODO)
2. Add two-way binding for form controls
3. Implement TableView data source
4. Add more examples

### Long Term
1. Performance optimizations (view caching)
2. Accessibility improvements
3. Animation support
4. More advanced layout options

## File Changes Summary

### Modified Files
- `src/event.rs` - Added `CallbackId` type
- `src/view.rs` - Added style modifiers, documentation, `Alignment` enum
- `src/app.rs` - Improved documentation
- `src/state.rs` - Added helper methods, documentation
- `src/error.rs` - Enhanced error types
- `src/lib.rs` - Updated prelude exports

### New Files
- `CONTRIBUTING.md` - Contributor guide
- `.github/workflows/ci.yml` - CI/CD configuration
- `scripts/quality-check.sh` - Quality check script
- `CHANGELOG.md` - Change tracking

## Testing

All improvements maintain backward compatibility with existing code. No breaking changes were introduced.

```bash
# Run all checks
./scripts/quality-check.sh

# Or individually:
cargo test
cargo clippy
cargo doc
cargo build --examples
```

## Conclusion

These improvements enhance the codebase's maintainability, developer experience, and code quality while maintaining the project's core philosophy of simplicity (KISS), avoiding repetition (DRY), and proper separation of concerns (SoC).