Add comprehensive documentation to Audioleaf codebase

[WeekendSuperhero]

Overview

This PR adds extensive documentation throughout the Audioleaf codebase, improving code maintainability and developer experience. The documentation covers all major modules and their public APIs.

Changes Summary

• 755 additions, 52 deletions across 14 files
• Comprehensive doc comments for public functions, structs, and modules
• Updated dependency versions in Cargo.lock

Documentation Added

Core Application (app.rs)

• Documented App::new() constructor with details on TUI initialization and visualizer setup
• Added docs for main event loop (run()), event-to-message conversion, and state updates
• Documented rendering system for effect list, visualizer, and help views

Audio Processing (audio.rs, processing.rs)

• Documented audio device selection and loopback detection logic
• Added FFT implementation details and spectrum processing documentation
• Explained color update algorithm with velocity-based transitions

Configuration (config.rs)

• Documented configuration parsing from TOML files
• Added details on TUI and visualizer configuration options
• Explained path resolution and device discovery via SSDP

Graphical Layout (graphical_layout.rs)

• Comprehensive module-level documentation for the visualization system
• Detailed function docs for panel rendering, controller attachment, and mouse interaction
• Documented color mapping scheme for different panel shapes

Nanoleaf Integration (nanoleaf.rs)

• Documented device connection and authentication flow
• Added API endpoint documentation for panel layout retrieval
• Explained device initialization and effect management

Utility Functions (utils.rs)

• Documented TUI initialization and cleanup procedures
• Added docs for HTTP request helpers (GET/POST/PUT)
• Explained interactive prompts and user input handling

Layout Visualization (layout_visualizer.rs)

• Documented shape type mapping from Nanoleaf IDs
• Added details on layout parsing from JSON responses
• Explained textual and graphical layout display

Visualizer (visualizer.rs)

• Documented visualizer initialization with UDP and audio setup
• Explained audio callback creation and sample processing
• Detailed the main processing thread and its event loop

Dependency Updates

Minor version updates to several dependencies:

• reqwest: 0.12.24 → 0.12.25
• tower-http: 0.6.7 → 0.6.8
• icu_properties: 2.1.1 → 2.1.2
• simd-adler32: 0.3.7 → 0.3.8

Testing

• No functional changes to code logic
• Documentation-only additions with minor dependency updates
• Existing functionality remains unchanged