Build a User Management API with ASP.NET Core

Problem/Feature Description

A SaaS startup needs a user management API built with ASP.NET Core and C#. A React single-page app hosted on https://app.example.com will consume this API. The API will run behind an AWS Application Load Balancer in production.

The API needs the following endpoints:

• POST /api/users/register -- create a new user account (accepts email, username, password, displayName)
• POST /api/users/login -- authenticate and return a JWT token
• GET /api/users/me -- return the current user's profile (requires valid JWT in Authorization header)
• PUT /api/users/me -- update the current user's profile (accepts displayName, bio)
• GET /api/users -- list all users (admin only, supports ?page=1&pageSize=20)
• DELETE /api/users/{id} -- deactivate a user account (admin only)

Use an in-memory list as the data store. Hash passwords before storing. The JWT secret and allowed origins should come from configuration. Users have Id, Email, Username, PasswordHash, DisplayName, Bio, Role (User or Admin), IsActive, and CreatedAt fields.

Output Specification

Produce:

• Program.cs -- Application entry point with all service registration and middleware pipeline
• Controllers/UsersController.cs -- Controller with user management endpoints
• Models/ -- Request DTOs and User entity
• Services/AuthService.cs -- JWT token generation and password hashing
• appsettings.json -- Configuration file (no real secrets)
• MyApp.csproj -- Project file with required NuGet packages