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/Storage/IStorageService.cs

@@ -0,0 +1,8 @@
+namespace Govor.Application.Storage;
+
+public interface IStorageService
+{
+    Task<string> SaveAsync(byte[] data, string fileName);
+    Task<Stream> LoadAsync(string url);
+    Task RemoveAsync(string url);
+}

Govor.Application/Storage/LocalStorageService.cs

@@ -0,0 +1,83 @@
+namespace Govor.Application.Storage;
+
+public class LocalStorageService : IStorageService
+{
+    private readonly string _storagePath;
+    
+    public LocalStorageService(string contentRootPath)
+    {
+        _storagePath = Path.Combine(contentRootPath, "uploads");
+        
+        if (!Directory.Exists(_storagePath))
+        {
+            Directory.CreateDirectory(_storagePath);
+        }
+    }
+    
+    public async Task<string> SaveAsync(byte[] data, string fileName)
+    {
+        if(data is null || data.Length == 0) 
+            throw new ArgumentException("Invalid file", nameof(data));
+        
+        if(fileName is null || fileName.Length == 0)
+            throw new ArgumentException("Invalid file name", nameof(fileName));
+        
+        var date = DateTime.UtcNow.ToString("yyyy/MM");
+        
+        var folder = Path.Combine(_storagePath, date);
+        Directory.CreateDirectory(folder);
+        
+        var uniqueFileName = $"{Guid.NewGuid()}_{Path.GetFileName(fileName)}";
+        var fullPath = Path.Combine(folder, uniqueFileName);
+        
+        await using var stream = new FileStream(fullPath, FileMode.Create);
+        await stream.WriteAsync(data, 0, data.Length);
+        
+        return Path.Combine(date, uniqueFileName);
+    }
+
+    public async Task<Stream> LoadAsync(string url)
+    {
+        var filePath = Path.Combine(_storagePath, url); 
+
+        if (!File.Exists(filePath))
+            throw new FileNotFoundException("File not found.", filePath);
+
+        return new FileStream(filePath, FileMode.Open, FileAccess.Read);
+    }
+
+    public async Task RemoveAsync(string url)
+    {
+        if (string.IsNullOrWhiteSpace(url))
+            throw new ArgumentException("Invalid file url");
+        
+        var rootPath = Path.GetFullPath(_storagePath);
+        
+        var fullPath = Path.GetFullPath(Path.Combine(rootPath, url));
+        
+        if (!fullPath.StartsWith(rootPath, StringComparison.OrdinalIgnoreCase))
+            throw new UnauthorizedAccessException("Invalid file path");
+
+        if (!File.Exists(fullPath))
+            return;
+
+        try
+        {
+            var fileInfo = new FileInfo(fullPath);
+            if (fileInfo.IsReadOnly)
+                fileInfo.IsReadOnly = false;
+
+            File.Delete(fullPath);
+        }
+        catch (IOException ex)
+        {
+            throw new IOException($"Failed to delete file: {fullPath}", ex);
+        }
+        catch (UnauthorizedAccessException ex)
+        {
+            throw new UnauthorizedAccessException($"No access to delete file: {fullPath}", ex);
+        }
+
+        await Task.CompletedTask;
+    }
+}