feat: Devin 分组放开 Messages 调度开关可见性与默认放行

- 分组编辑/创建的 allow_messages_dispatch 区块对 devin 平台显示
- 用户私有 devin 分组默认允许 /v1/messages 分发（与桥接能力一致）

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

Author: Open-Pixel-AI

backend/internal/service/user_private_group_service.go

@@ -242,7 +242,7 @@ func normalizePrivateGroupPlatform(platform string) string {
 
 func defaultPrivateGroupAllowMessagesDispatch(platform string) bool {
 	switch normalizePrivateGroupPlatform(platform) {
-	case PlatformOpenAI, PlatformOpencode, PlatformKimi, PlatformZhipu, PlatformDeepseek, PlatformMiniMax, PlatformQwen, PlatformAPIAggregation:
+	case PlatformOpenAI, PlatformOpencode, PlatformDevin, PlatformKimi, PlatformZhipu, PlatformDeepseek, PlatformMiniMax, PlatformQwen, PlatformAPIAggregation:
 		return true
 	default:
 		return false

frontend/src/views/admin/GroupsView.vue

@@ -1287,9 +1287,9 @@
           </div>
         </div>
 
-        <!-- OpenAI Messages 调度配置（仅 openai 平台） -->
+        <!-- OpenAI Messages 调度配置（仅 openai/devin 平台） -->
         <div
-          v-if="createForm.platform === 'openai'"
+          v-if="createForm.platform === 'openai' || createForm.platform === 'devin'"
           class="border-t border-gray-200 dark:border-dark-400 pt-4 mt-4"
         >
           <h4 class="text-sm font-medium text-gray-700 dark:text-gray-300 mb-3">
@@ -2607,9 +2607,9 @@
           </div>
         </div>
 
-        <!-- OpenAI Messages 调度配置（仅 openai 平台） -->
+        <!-- OpenAI Messages 调度配置（仅 openai/devin 平台） -->
         <div
-          v-if="editForm.platform === 'openai'"
+          v-if="editForm.platform === 'openai' || editForm.platform === 'devin'"
           class="border-t border-gray-200 dark:border-dark-400 pt-4 mt-4"
         >
           <h4 class="text-sm font-medium text-gray-700 dark:text-gray-300 mb-3">