完善ktor后端项目

ktor/src/main/kotlin/ink/snowflake/server/model/database/AISessionsTable.kt

@@ -0,0 +1,12 @@
+package ink.snowflake.server.model.database
+
+import org.jetbrains.exposed.v1.core.dao.id.UUIDTable
+import org.jetbrains.exposed.v1.datetime.timestampWithTimeZone
+
+// 定义 AI 表
+object AISessionsTable : UUIDTable("ai_chat_sessions") {
+    val userId = uuid("user_id")
+    val title = varchar("title", 255).nullable()
+    val createdAt = timestampWithTimeZone("created_at")
+    val updatedAt = timestampWithTimeZone("updated_at")
+}

ktor/src/main/kotlin/ink/snowflake/server/model/response/SessionListResponse.kt

@@ -0,0 +1,10 @@
+package ink.snowflake.server.model.response
+
+import kotlinx.serialization.Contextual
+import kotlinx.serialization.Serializable
+import java.util.UUID
+
+@Serializable
+data class SessionListResponse(
+    @Contextual val id: UUID, val title: String?, val updatedAt: String
+)

ktor/src/main/kotlin/ink/snowflake/server/utils/Log/UnauthorizedException.kt

@@ -0,0 +1,4 @@
+package ink.snowflake.server.utils.Log
+
+// 这里暂时没用，因为调用的地方，也就是从token获取id，一定是被authenticate包裹的，也就是传入的token一定是有用的，没用的会直接被返回401
+class UnauthorizedException(message: String) : RuntimeException(message)