feat: 为 Anthropic DTO 添加 signature、stop_sequence、cache_creation 和 service_tier 字段

在 Yi.Framework.AiHub.Domain.Shared/Dtos/Anthropic/AnthropicChatCompletionDto.cs 中新增字段：
- AnthropicChatCompletionDto: Signature、StopSequence（带 JsonPropertyName）
- AnthropicChatCompletionDtoContentBlock: signature（小写字段）
- AnthropicCompletionDtoUsage: CacheCreation、ServiceTier（带 JsonPropertyName）

Yi.Abp.Net8/module/ai-hub/Yi.Framework.AiHub.Domain.Shared/Dtos/Anthropic/AnthropicChatCompletionDto.cs

@@ -39,6 +39,11 @@ public class AnthropicChatCompletionDtoDelta
     [JsonPropertyName("partial_json")] public string? PartialJson { get; set; }
 
     [JsonPropertyName("stop_reason")] public string? StopReason { get; set; }
+    
+    [JsonPropertyName("signature")] public string? Signature { get; set; }
+    
+    [JsonPropertyName("stop_sequence")] public string? StopSequence { get; set; }
+    
 }
 
 public class AnthropicChatCompletionDtoContentBlock
@@ -103,6 +108,7 @@ public class AnthropicChatCompletionDtoContent
     [JsonPropertyName("partial_json")] public string? PartialJson { get; set; }
 
     public string? signature { get; set; }
+    
 }
 
 public class AnthropicCompletionDtoUsage
@@ -118,6 +124,12 @@ public class AnthropicCompletionDtoUsage
     [JsonPropertyName("output_tokens")] public int? OutputTokens { get; set; }
 
     [JsonPropertyName("server_tool_use")] public AnthropicServerToolUse? ServerToolUse { get; set; }
+    
+    [JsonPropertyName("cache_creation")] public object? CacheCreation { get; set; }
+
+    [JsonPropertyName("service_tier")] public string? ServiceTier { get; set; }
+
+
 }
 
 public class AnthropicServerToolUse