Program.cs

using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;
using Microsoft.IdentityModel.Tokens;
using System.Text;

var builder = WebApplication.CreateBuilder(args);

// PostgreSQL connection
builder.Services.AddDbContext<AppDbContext>(options =>
    options.UseNpgsql(builder.Configuration.GetConnectionString("DefaultConnection")));

builder.Services.AddIdentity<IdentityUser, IdentityRole>()
    .AddEntityFrameworkStores<AppDbContext>()
    .AddDefaultTokenProviders();

var jwtSettings = builder.Configuration.GetSection("Jwt").Get<JwtSettings>();

builder.Services.AddSingleton<JwtSettings>(jwtSettings);

builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
    .AddJwtBearer(options =>
    {
        options.TokenValidationParameters = new TokenValidationParameters
        {
            ValidateIssuer = true,
            ValidateAudience = true,
            ValidateLifetime = true,
            ValidateIssuerSigningKey = true,
            ValidIssuer = jwtSettings.Issuer,
            ValidAudience = jwtSettings.Audience,
            IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(jwtSettings.Key))
        };
    });

builder.Services.AddAuthorization();

// Add services to the container.
// Learn more about configuring OpenAPI at https://aka.ms/aspnet/openapi
builder.Services.AddOpenApi();

var app = builder.Build();

// Ensure database is created and apply migrations
using (var scope = app.Services.CreateScope())
{
    var db = scope.ServiceProvider.GetRequiredService<AppDbContext>();
    db.Database.Migrate(); // applies any pending migrations
}

app.UseAuthentication();
app.UseAuthorization();

app.MapAuthenticationEndpoints();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.MapOpenApi();
}

app.UseHttpsRedirection();

app.Run();