Flutter GUI Tool Integration for MIDI-CI

This PR adds a complete Flutter GUI tool integration to the midicci repository, providing a cross-platform alternative to the existing Qt tool.

Overview

The Flutter MIDI-CI tool (tools/flutter-ci-tool/) integrates with the existing C++ business logic through the primary entry points:

• CIToolRepository - Configuration and logging management
• CIDeviceModel - Device state management and MIDI-CI operations
• CIDeviceManager - MIDI device enumeration and connection management

Key Features

✅ CMake Integration - Flutter builds are triggered by custom CMake commands from the top-level build system
✅ Optional Build - Flutter tool is only built when Flutter SDK is detected, following the same pattern as the Qt tool
✅ Cross-Platform Support - Supports Linux, macOS, Windows, Android, iOS, and Web
✅ C++ Wrapper Library - Clean platform channel integration with midicci-tooling library
✅ 4-Screen Interface - Complete UI matching the original Kotlin Compose Multiplatform app:

• Initiator - Send discovery messages and manage client connections
• Responder - Configure local profiles and properties
• Log - View MIDI-CI message logs with filtering
• Settings - Device configuration and application settings

Architecture

Flutter App (Dart)
    ↓ Platform Channels
C++ Wrapper Library (midicci-flutter-wrapper)
    ↓ Direct API calls
midicci-tooling Library (CIToolRepository, CIDeviceModel, CIDeviceManager)
    ↓ 
midicci Core Library

Build Integration

The Flutter tool follows the same CMake integration pattern as the existing Qt tool:

# Make Flutter tool optional - use Flutter detection
find_program(FLUTTER_EXECUTABLE flutter)
if(FLUTTER_EXECUTABLE)
    add_subdirectory(flutter-ci-tool)
else()
    message(STATUS "Flutter not found, skipping flutter-ci-tool")
endif()

Custom CMake targets:

• flutter-pub-get - Install Flutter dependencies
• flutter-build - Build Flutter application
• flutter-run - Run Flutter app in development mode

Testing

✅ Flutter Analysis - All Flutter code passes flutter analyze with no issues
✅ CMake Build - Successfully integrates with midicci build system
✅ Dependency Resolution - Flutter dependencies install correctly via CMake
✅ C++ Wrapper - Compiles and links with midicci-tooling library

Files Added

• tools/flutter-ci-tool/ - Complete Flutter application
• tools/flutter-ci-tool/CMakeLists.txt - CMake configuration
• tools/flutter-ci-tool/native/ - C++ wrapper for platform channels
• tools/flutter-ci-tool/lib/ - Flutter UI implementation
• Updated tools/CMakeLists.txt - Added Flutter tool integration

Verification

The implementation has been verified to:

1. Build successfully with CMake when Flutter is available
2. Skip gracefully when Flutter is not installed
3. Pass all Flutter static analysis checks
4. Follow existing midicci repository patterns and conventions

Link to Devin run: https://app.devin.ai/sessions/98cd60952f66496aaec0341c23ec0288
Requested by: Atsushi Eno (atsushieno@gmail.com)