Add CI/CD pipeline with multi-platform builds and tests

[WeekendSuperhero]

Overview

This PR introduces a comprehensive CI/CD pipeline using GitHub Actions to automate building, testing, and quality checks for the Audioleaf project.

Changes

• Added .github/workflows/build.yaml workflow that runs on:
  • All pull requests
  • Pushes to main branch

Features

Multi-Platform Support

• Builds and tests on Ubuntu, macOS, and Windows
• Uses stable Rust toolchain

Quality Checks

• Code formatting verification with cargo fmt
• Linting with cargo clippy (treats warnings as errors)
• Build in release mode
• Unit tests execution

Performance Optimizations

• Caches cargo registry, git index, and target directory
• Reduces build times on subsequent runs

Platform-Specific Setup

• Automatically installs required system dependencies on Ubuntu (libasound2-dev, pkg-config)

Testing

The workflow will run automatically on this PR to validate the setup.