feat: 完成云同步、语音控制与多平台扩展基础架构搭建

本次提交完成了项目核心基础架构升级：
1. 新增动态API中间件与权限控制系统，支持匿名/鉴权接口分离
2. 搭建云同步服务体系，包含认证、任务同步、安全策略等核心模块
3. 实现语音控制全链路，从STT/意图解析到命令执行
4. 新增任务类型、附件实体与相关仓储接口
5. 重构前端配置与代理规则，统一后端端口为5057
6. 新增多平台测试项目与CI脚本优化
7. 完善项目文档与代码注释规范

移除了旧版迁移文件与冗余代理配置，调整项目结构适配跨平台部署需求。

test/Hua.Todo.Host.Tests/CloudSyncDtoTests.cs

@@ -0,0 +1,137 @@
+using System.Text.Json;
+using Hua.Todo.Application.Services.CloudSync.Models;
+using Hua.Todo.Core.Entities;
+using Xunit;
+
+namespace Hua.Todo.Host.Tests;
+
+/// <summary>
+/// CloudSync DTO 单元测试。
+/// </summary>
+public class CloudSyncDtoTests
+{
+    /// <summary>
+    /// 测试 CloudTaskItem JSON 序列化使用 camelCase。
+    /// </summary>
+    [Fact]
+    public void CloudTaskItem_Serialization_UsesCamelCase()
+    {
+        // Arrange
+        var item = new CloudTaskItem
+        {
+            Id = Guid.Parse("12345678-1234-1234-1234-123456789012"),
+            Title = "Test",
+            Priority = TaskPriority.High,
+            IsCompleted = true,
+            CreationTime = new DateTime(2024, 1, 1, 0, 0, 0, DateTimeKind.Utc),
+            LastModificationTime = new DateTime(2024, 1, 2, 0, 0, 0, DateTimeKind.Utc),
+            IsDeleted = false
+        };
+
+        // Act
+        var json = JsonSerializer.Serialize(item);
+        var deserialized = JsonSerializer.Deserialize<Dictionary<string, object>>(json);
+
+        // Assert
+        Assert.NotNull(deserialized);
+        Assert.True(deserialized.ContainsKey("id"));
+        Assert.True(deserialized.ContainsKey("title"));
+        Assert.True(deserialized.ContainsKey("priority"));
+        Assert.True(deserialized.ContainsKey("isCompleted"));
+        Assert.True(deserialized.ContainsKey("creationTime"));
+        Assert.True(deserialized.ContainsKey("lastModificationTime"));
+        Assert.True(deserialized.ContainsKey("isDeleted"));
+    }
+
+    /// <summary>
+    /// 测试 CloudTaskUpsert JSON 反序列化。
+    /// </summary>
+    [Fact]
+    public void CloudTaskUpsert_Deserialization_FromCamelCase()
+    {
+        // Arrange
+        var json = @"{""id"":""12345678-1234-1234-1234-123456789012"",""title"":""Test Task"",""priority"":2,""isCompleted"":true,""lastModificationTime"":""2024-01-02T00:00:00Z""}";
+
+        // Act
+        var upsert = JsonSerializer.Deserialize<CloudTaskUpsert>(json);
+
+        // Assert
+        Assert.NotNull(upsert);
+        Assert.Equal(Guid.Parse("12345678-1234-1234-1234-123456789012"), upsert.Id);
+        Assert.Equal("Test Task", upsert.Title);
+        Assert.Equal(TaskPriority.High, upsert.Priority);
+        Assert.True(upsert.IsCompleted);
+    }
+
+    /// <summary>
+    /// 测试 SyncRequest JSON 反序列化。
+    /// </summary>
+    [Fact]
+    public void SyncRequest_Deserialization()
+    {
+        // Arrange
+        var json = @"{
+            ""upserts"": [
+                {""id"":""12345678-1234-1234-1234-123456789012"",""title"":""Task 1""},
+                {""title"":""Task 2""}
+            ],
+            ""deletes"": [""87654321-4321-4321-4321-210987654321""]
+        }";
+
+        // Act
+        var request = JsonSerializer.Deserialize<SyncRequest>(json);
+
+        // Assert
+        Assert.NotNull(request);
+        Assert.Equal(2, request.Upserts.Count);
+        Assert.Single(request.Deletes);
+    }
+
+    /// <summary>
+    /// 测试 SyncResponse JSON 序列化。
+    /// </summary>
+    [Fact]
+    public void SyncResponse_Serialization()
+    {
+        // Arrange
+        var response = new SyncResponse
+        {
+            ServerTimeUtc = new DateTime(2024, 1, 1, 12, 0, 0, DateTimeKind.Utc),
+            Tasks = new List<CloudTaskItem>
+            {
+                new CloudTaskItem
+                {
+                    Id = Guid.NewGuid(),
+                    Title = "Task 1",
+                    Priority = TaskPriority.Medium
+                }
+            }
+        };
+
+        // Act
+        var json = JsonSerializer.Serialize(response);
+        var deserialized = JsonSerializer.Deserialize<Dictionary<string, object>>(json);
+
+        // Assert
+        Assert.NotNull(deserialized);
+        Assert.True(deserialized.ContainsKey("serverTimeUtc"));
+        Assert.True(deserialized.ContainsKey("tasks"));
+    }
+
+    /// <summary>
+    /// 测试 Guid 类型的 JSON 序列化。
+    /// </summary>
+    [Fact]
+    public void Guid_Serialization_IsString()
+    {
+        // Arrange
+        var guid = Guid.NewGuid();
+        var item = new CloudTaskItem { Id = guid };
+
+        // Act
+        var json = JsonSerializer.Serialize(item);
+
+        // Assert
+        Assert.Contains(guid.ToString(), json);
+    }
+}