ANKE-3: Migrate VB.NET Sudoku application to C#

[devin-ai-integration]

Summary

This PR completes ticket ANKE-3 by migrating the VB.NET Sudoku Windows Forms application to C#. The migration creates a complete C# equivalent under windowsforms/Sudoku/CS/sudoku/ while preserving the original VB.NET version.

Key Changes

Project Structure & Configuration

• Created new C# project structure mirroring the VB.NET organization
• Converted sudoku.vbproj to sudoku.csproj with C#-specific configuration
• Removed VB.NET specific properties (OptionInfer, OptionStrict, LangVersion)
• Added EnableWindowsTargeting=true for cross-platform builds
• Added Program.cs as application entry point with proper Windows Forms bootstrapping

Core Logic Migration (Game.vb → Game.cs)

• Converted VB.NET events to C# Action<int[][]> delegates
• Migrated jagged arrays from VB.NET syntax to proper C# initialization
• Converted Do...Loop to do...while loop in constraint satisfaction algorithm
• Updated integer division operator \ to / for 3x3 square calculation
• Preserved LINQ-based constraint satisfaction logic with Intersect() operations

UI Migration (Form1.vb → Form1.cs)

• Replaced VB.NET WithEvents/Handles pattern with explicit C# event subscription
• Converted Sub methods to void methods with proper signatures
• Updated Me. references to this.
• Preserved DataGridView manipulation logic for Sudoku grid display

Designer Code Migration (Form1.Designer.vb → Form1.Designer.cs)

• Converted control declarations from Friend WithEvents to private fields
• Updated resource loading syntax and designer attributes
• Maintained exact UI layout with 9x9 DataGridView grid structure

Resources Copied

• sudoku_icon.ico - Application icon
• Form1.resx - Windows Forms resources and embedded icon data
• Sudoku Image.jpg - Additional image resource

⚠️ Review Focus Areas

High Priority - Functionality Critical:

1. Game.cs CreateNewGame() method - Complex constraint satisfaction algorithm with nested loops and LINQ operations
2. Event subscription in Form1.cs constructor - Critical for UI-Game communication
3. Array initialization patterns - Jagged arrays must be properly initialized

Medium Priority - Runtime Stability:
4. Resource loading and icon references - Ensure proper resource embedding
5. Project configuration - Verify build settings and dependencies
6. UI event handlers - Check button clicks and combo box changes work correctly

Testing Status

✅ Build: Successfully compiles with dotnet build
⚠️ Runtime: Unable to test locally due to .NET 7.0 vs 8.0 environment mismatch
🔄 Functionality: Requires manual verification on target environment

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Requested by: @ankehao-dev
Devin Session: https://app.devin.ai/sessions/c6828256f4d9407a8e058436415f25c0
Ticket: ANKE-3

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