Init Sample: Create .NET vulnerable dependencies sample repository

[Copilot]

This PR transforms the repository into a complete sample demonstrating vulnerable dependencies in a .NET solution with Central Package Management (CPM).

What's Added

Solution Structure:

• Created a .NET 8 solution with three distinct project types:
  • VulnerableWebApi - ASP.NET Core Web API with JWT authentication and JSON handling
  • VulnerableLibrary - Class library with logging and token processing capabilities
  • VulnerableConsole - Console application with database connectivity

Central Package Management:

• Implemented CPM using Directory.Packages.props for centralized version control
• All package versions are managed in a single location across all projects

Vulnerable Dependencies:
The sample includes intentionally vulnerable packages to demonstrate security scanning:

Package	Version	Severity	Project
Newtonsoft.Json	10.0.1	High	VulnerableWebApi
Microsoft.Data.SqlClient	1.0.19239.1	High/Moderate	VulnerableConsole
System.IdentityModel.Tokens.Jwt	5.1.0	Moderate	VulnerableLibrary
Microsoft.AspNetCore.Authentication.JwtBearer	3.1.0	Moderate	VulnerableWebApi

Security Warnings Generated:
Building the solution produces 12+ vulnerability warnings (NU1902/NU1903), demonstrating how .NET's built-in security scanning detects vulnerable packages during restore and build operations.

Sample Code:
Each project includes realistic code that uses the vulnerable dependencies:

• JWT token authentication and processing
• JSON serialization/deserialization
• Database connection handling
• Structured logging with NLog

Documentation:
Comprehensive README.md covering:

• Vulnerability details with CVE links
• Educational use cases (security training, tool testing, DevOps pipeline testing)
• Build and run instructions
• Remediation guidance

This sample serves as an educational tool for understanding dependency vulnerabilities and testing security scanning tools in .NET environments.

Fixes #1.

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[Copilot]

@felickz 👋 This repository doesn't have Copilot instructions. With Copilot instructions, I can understand the repository better, work faster and produce higher quality PRs.

I can generate a .github/copilot-instructions.md file for you automatically. Click here to open a pre-filled issue and assign it to me. I'll write the instructions, and then tag you for review.