Add comprehensive GitHub Copilot instructions for netcorepal-cloud-framework

[Copilot]

This PR adds a comprehensive .github/copilot-instructions.md file that provides GitHub Copilot with detailed instructions for working effectively with the netcorepal-cloud-framework repository.

What's Added

The instructions file includes:

• Clear directives to always follow the instructions first before searching or exploring
• Exact .NET SDK setup with specific version requirements (9.0.100-rc.1.24452.12)
• Validated build commands with precise timing expectations and "NEVER CANCEL" warnings
• External dependency setup for Docker containers (Redis, RabbitMQ, PostgreSQL/MySQL)
• Comprehensive troubleshooting for common development issues
• Project structure overview explaining the 37+ framework components
• Manual testing scenarios with expected outcomes for validation

Key Features

Build & Test Timing (All Validated)

• dotnet restore: ~50 seconds (NEVER CANCEL - set 90+ second timeout)
• dotnet build: ~41 seconds for full solution (NEVER CANCEL - set 60+ second timeout)
• Unit tests: 2-6 seconds per project when using --framework net9.0
• Integration tests: Require external Docker dependencies

Framework Coverage

The instructions cover all major framework areas:

• Domain-Driven Design abstractions and source generators
• Repository pattern with Entity Framework Core
• Distributed transactions using CAP
• Context passing for HTTP and messaging
• Multi-environment and multi-tenant support
• ASP.NET Core extensions and middleware

Validation Scenarios

All commands and scenarios in the instructions have been tested:

• SDK installation and verification
• Build process validation
• Unit test execution
• Sample web application startup
• Common error scenarios and troubleshooting

Example Usage

The instructions enable Copilot to quickly understand how to:

# Install exact .NET version required
./dotnet-install.sh --version 9.0.100-rc.1.24452.12

# Build with proper timing expectations  
dotnet build -c Release --no-restore  # 41s, NEVER CANCEL

# Run unit tests without external dependencies
dotnet test --framework net9.0

# Test the sample web application
dotnet run --project test/NetCorePal.Web/NetCorePal.Web.csproj

This ensures that GitHub Copilot can work efficiently with this Domain-Driven Design framework without trial-and-error or time-consuming exploration.

Fixes #10.

---

💬 Share your feedback on Copilot coding agent for the chance to win a $200 gift card! Click here to start the survey.