Global Exception Handling Middleware for ASP.NET Core

Act as a Senior ASP.NET Core Architect.

Design and implement a reusable global exception-handling middleware for an ASP.NET Core Web API that:

• Catches all unhandled exceptions across the request pipeline
• Differentiates between validation errors, business exceptions, and system exceptions
• Logs errors using ILogger (and optionally Application Insights or Serilog)
• Returns consistent, standardized API responses following REST best practices
• Supports custom HTTP status codes per exception type
• Hides sensitive internal details in production environments
• Is clean, testable, and reusable across multiple projects

The solution should include:

• Middleware implementation code
• A standardized API response model (error contract)
• Custom exception examples
• Registration in Program.cs
• Example JSON error responses
• Best-practice explanations and extensibility tips

Use production-ready code with proper naming conventions and comments.