fix: AiProviderPresetSeeder 字典初始化器缺失逗号导致编译失败

第 27 行末尾缺逗号，下一行被解析为 string 索引赋值，
SDK 10 报 CS1503 (cannot convert 'string' to 'int')。
补上逗号并通过 dotnet build 全解决方案编译验证。

Author: 239573049

src/OpenDeepWiki/Services/AI/AiProviderPresetSeeder.cs

@@ -24,7 +24,7 @@ public sealed class AiProviderPresetSeeder : IAiProviderPresetSeeder
             ["copilot-oauth"] = "https://github.githubassets.com/favicons/favicon.png",
             ["orcarouter"] = "https://www.orcarouter.ai/favicon.ico",
             ["requesty"] = "https://www.requesty.ai/favicon.ico",
-            ["cheaperinference"] = "https://www.cheaperinference.com/icon.svg"
+            ["cheaperinference"] = "https://www.cheaperinference.com/icon.svg",
             ["api-route"] = "https://www.api-route.com/images/logo-ginkgo.png"
         };