fix: 修复用量统计线程问题并完善搜索与Token计算逻辑

- OnlineSearch 增加 daysAgo 非法值保护，避免无效时间范围
- 修复 UsageStatistics 中 Prompt/Completion Token 为 0 时的统计异常
- 引入独立 UnitOfWork，解决流式处理下的并发与事务问题
- 确保用量统计、系统消息与尊享包扣减的原子性
- 补充前端 Element Plus 组件类型声明
- 统一并优化部分代码格式，不影响业务逻辑

Yi.Abp.Net8/module/ai-hub/Yi.Framework.AiHub.Domain/Mcp/OnlineSearchTool.cs

@@ -29,8 +29,14 @@ public class OnlineSearchTool : ISingletonDependency
     }
 
     [YiAgentTool("联网搜索"), DisplayName("OnlineSearch"), Description("进行在线搜索，获取最新的网络信息，近期信息是7天，实时信息是1天")]
-    public async Task<string> OnlineSearch([Description("搜索关键字")]string keyword, [Description("距离现在多久天")]int? daysAgo = null)
+    public async Task<string> OnlineSearch([Description("搜索关键字")] string keyword,
+        [Description("距离现在多久天")] int? daysAgo = null)
     {
+        if (daysAgo <= 0)
+        {
+            daysAgo = 1;
+        }
+
         if (string.IsNullOrWhiteSpace(keyword))
         {
             return "搜索关键词不能为空";
@@ -149,8 +155,7 @@ public class OnlineSearchTool : ISingletonDependency
 /// </summary>
 public class BaiduSearchRequest
 {
-    [JsonPropertyName("messages")]
-    public List<BaiduSearchMessage> Messages { get; set; } = new();
+    [JsonPropertyName("messages")] public List<BaiduSearchMessage> Messages { get; set; } = new();
 
     [JsonPropertyName("search_filter")]
     [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
@@ -162,8 +167,7 @@ public class BaiduSearchRequest
 /// </summary>
 public class BaiduSearchFilter
 {
-    [JsonPropertyName("range")]
-    public BaiduSearchRange? Range { get; set; }
+    [JsonPropertyName("range")] public BaiduSearchRange? Range { get; set; }
 }
 
 /// <summary>
@@ -171,8 +175,7 @@ public class BaiduSearchFilter
 /// </summary>
 public class BaiduSearchRange
 {
-    [JsonPropertyName("page_time")]
-    public BaiduSearchPageTime? PageTime { get; set; }
+    [JsonPropertyName("page_time")] public BaiduSearchPageTime? PageTime { get; set; }
 }
 
 /// <summary>
@@ -180,11 +183,9 @@ public class BaiduSearchRange
 /// </summary>
 public class BaiduSearchPageTime
 {
-    [JsonPropertyName("gte")]
-    public string? Gte { get; set; }
+    [JsonPropertyName("gte")] public string? Gte { get; set; }
 
-    [JsonPropertyName("lte")]
-    public string? Lte { get; set; }
+    [JsonPropertyName("lte")] public string? Lte { get; set; }
 }
 
 /// <summary>
@@ -192,11 +193,9 @@ public class BaiduSearchPageTime
 /// </summary>
 public class BaiduSearchMessage
 {
-    [JsonPropertyName("role")]
-    public string Role { get; set; } = "user";
+    [JsonPropertyName("role")] public string Role { get; set; } = "user";
 
-    [JsonPropertyName("content")]
-    public string Content { get; set; } = "";
+    [JsonPropertyName("content")] public string Content { get; set; } = "";
 }
 
 /// <summary>
@@ -204,11 +203,9 @@ public class BaiduSearchMessage
 /// </summary>
 public class BaiduSearchResponse
 {
-    [JsonPropertyName("request_id")]
-    public string? RequestId { get; set; }
+    [JsonPropertyName("request_id")] public string? RequestId { get; set; }
 
-    [JsonPropertyName("references")]
-    public List<BaiduSearchReference>? References { get; set; }
+    [JsonPropertyName("references")] public List<BaiduSearchReference>? References { get; set; }
 }
 
 /// <summary>
@@ -216,23 +213,17 @@ public class BaiduSearchResponse
 /// </summary>
 public class BaiduSearchReference
 {
-    [JsonPropertyName("id")]
-    public int Id { get; set; }
+    [JsonPropertyName("id")] public int Id { get; set; }
 
-    [JsonPropertyName("url")]
-    public string? Url { get; set; }
+    [JsonPropertyName("url")] public string? Url { get; set; }
 
-    [JsonPropertyName("title")]
-    public string? Title { get; set; }
+    [JsonPropertyName("title")] public string? Title { get; set; }
 
-    [JsonPropertyName("date")]
-    public string? Date { get; set; }
+    [JsonPropertyName("date")] public string? Date { get; set; }
 
-    [JsonPropertyName("snippet")]
-    public string? Snippet { get; set; }
+    [JsonPropertyName("snippet")] public string? Snippet { get; set; }
 
-    [JsonPropertyName("website")]
-    public string? Website { get; set; }
+    [JsonPropertyName("website")] public string? Website { get; set; }
 }
 
 #endregion