✨ Add chat message handling and WebSocket integration

Introduce new `ChatService` for managing chat messages, including marking messages as read and checking read status. Add `WebSocketPacket` class for handling WebSocket communication and integrate it with `WebSocketService` to process chat-related packets. Enhance `ChatRoom` and `ChatMember` models with additional fields and relationships. Update `AppDatabase` to include new chat-related entities and adjust permissions for chat creation.

DysonNetwork.Sphere/Connection/WebSocketPacket.cs

@@ -0,0 +1,62 @@
+using System.Text.Json;
+
+public class WebSocketPacketType
+{
+    public const string Error = "error";
+}
+
+public class WebSocketPacket
+{
+    public string Type { get; set; } = null!;
+    public object Data { get; set; }
+    public string? ErrorMessage { get; set; }
+
+    /// <summary>
+    /// Creates a WebSocketPacket from raw WebSocket message bytes
+    /// </summary>
+    /// <param name="bytes">Raw WebSocket message bytes</param>
+    /// <returns>Deserialized WebSocketPacket</returns>
+    public static WebSocketPacket FromBytes(byte[] bytes)
+    {
+        var json = System.Text.Encoding.UTF8.GetString(bytes);
+        var jsonOpts = new JsonSerializerOptions
+        {
+            PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower,
+            DictionaryKeyPolicy = JsonNamingPolicy.SnakeCaseLower,
+        };
+        return JsonSerializer.Deserialize<WebSocketPacket>(json, jsonOpts) ??
+            throw new JsonException("Failed to deserialize WebSocketPacket");
+    }
+
+    /// <summary>
+    /// Deserializes the Data property to the specified type T
+    /// </summary>
+    /// <typeparam name="T">Target type to deserialize to</typeparam>
+    /// <returns>Deserialized data of type T</returns>
+    public T? GetData<T>()
+    {
+        if (Data == null)
+            return default;
+        if (Data is T typedData)
+            return typedData;
+
+        return JsonSerializer.Deserialize<T>(
+            JsonSerializer.Serialize(Data)
+        );
+    }
+
+    /// <summary>
+    /// Serializes this WebSocketPacket to a byte array for sending over WebSocket
+    /// </summary>
+    /// <returns>Byte array representation of the packet</returns>
+    public byte[] ToBytes()
+    {
+        var jsonOpts = new JsonSerializerOptions
+        {
+            PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower,
+            DictionaryKeyPolicy = JsonNamingPolicy.SnakeCaseLower,
+        };
+        var json = JsonSerializer.Serialize(this, jsonOpts);
+        return System.Text.Encoding.UTF8.GetBytes(json);
+    }
+}