Refactor: migrate Core -> Domain and reorganize projects

Large refactor that renames/moves core types into a new Govor.Domain surface and reorganizes the Application layer. Models, configurations, migrations and many files moved from Govor.Core/Govor.Data to Govor.Domain; numerous Application services, interfaces and implementations were relocated or added (authentication, friends, messages, medias, push notifications, user sessions, storage, synching, private chats, etc.). Tests updated to use Govor.Domain namespaces and adjusted project references (removed Govor.Data reference from API tests). Also updated API, Hub and mapping code and project files to reflect the new structure and naming. This is primarily a codebase-wide namespace and module reorganization to establish a Domain project and restructure application services.

Govor.Application/Authentication/AuthService.cs

@@ -0,0 +1,101 @@
+using Govor.Application.Authentication.Exceptions;
+using Govor.Application.Infrastructure.Validators;
+using Govor.Application.Users;
+using Govor.Domain;
+using Govor.Domain.Common;
+using Govor.Domain.Models;
+using Govor.Domain.Models.Users;
+using Microsoft.EntityFrameworkCore;
+
+namespace Govor.Application.Authentication;
+
+public class AuthService : IAccountService
+{
+    private readonly GovorDbContext _context; 
+    private readonly IPasswordHasher _passwordHasher;
+    private readonly IUserNameExistValidator _userNameExistValidator;
+    private readonly IUsernameValidator _usernameValidator;
+    
+    public AuthService(
+        GovorDbContext context,
+        IUserNameExistValidator existValidator,
+        IPasswordHasher passwordHasher,
+        IUsernameValidator usernameValidator)
+    {
+        _context = context;
+        _userNameExistValidator = existValidator;
+        _passwordHasher = passwordHasher;
+        _usernameValidator = usernameValidator;
+    }
+    
+    public async Task<Result<User>> RegistrationAsync(string name, string password, Invitation invitation)
+    {
+      
+        var validationResult = _usernameValidator.Validate(name);
+        if (validationResult.IsFailure)
+        {
+            return Result<User>.Failure(validationResult.Error);
+        }
+        
+        if (await _userNameExistValidator.IsUsernameExistsAsync(name))
+        {
+            return Result<User>.Failure(new Error(
+                 nameof(UserAlreadyExistException), 
+                $"User with username '{name}' already exists."));
+        }
+        
+        var passwordHash = _passwordHasher.Hash(password);
+        
+        var user = new User
+        {
+            Id = Guid.NewGuid(),
+            Username = name,
+            PasswordHash = passwordHash,
+            Description = string.Empty,
+            CreatedOn = DateOnly.FromDateTime(DateTime.UtcNow),
+            IconId = Guid.Empty,
+            WasOnline = DateTime.UtcNow,
+            InviteId = invitation.Id
+        };
+        
+       
+        await _context.Users.AddAsync(user);
+        
+        await SetRoleAsync(user, invitation);
+        
+        await _context.SaveChangesAsync();
+        
+        return user; // Success 
+    }
+
+    public async Task<Result<User>> LoginAsync(string name, string password)
+    {
+        var user = await _context.Users
+            .AsNoTracking()
+            .FirstOrDefaultAsync(u => u.Username == name);
+        
+        if (user is null)
+        {
+            return Result<User>.Failure(new Error(
+                nameof(UserNotRegisteredException), 
+                $"User '{name}' is not registered."));
+        }
+        
+        if (!_passwordHasher.Verify(password, user.PasswordHash))
+        {
+            return Result<User>.Failure(new Error(
+                nameof(InvalidOperationException), 
+                "The password provided is incorrect."));
+        }
+        
+        return user; // Success 
+    }
+    
+    private async Task SetRoleAsync(User user, Invitation invitation)
+    {
+        if (invitation.IsAdmin)
+        {
+            await _context.Admins.AddAsync(new Admin { UserId = user.Id });
+        }
+    }
+}