避免同名模型导致精选图片重复和计数偏差

同一 modelId 配置多个上游时，精选接口的模型关联会把一张图片返回多次，导致数量和分页偏大。改为为每张图片选择一个模型名称，保证图片记录和总数一致。

验证：生产只读数据包含同名模型两条，修正查询返回 6 个不同图片 ID、总数 6；TypeScript 检查通过。

app/api/featured/route.ts

@@ -58,12 +58,13 @@ export async function GET(request: NextRequest) {
           userName: user.name,
           userEmail: user.email,
           userDepartment: user.department,
-          modelName: aiModel.displayName,
+          modelName: sql<string | null>`(select ${aiModel.displayName} from ${aiModel}
+            where ${aiModel.modelId} = ${generatedImage.modelId}
+            order by ${aiModel.isEnabled} desc, ${aiModel.createdAt} desc, ${aiModel.id} asc limit 1)`,
           totalCount: sql<number>`count(*) over()::int`,
         })
         .from(generatedImage)
         .leftJoin(user, eq(generatedImage.userId, user.id))
-        .leftJoin(aiModel, eq(generatedImage.modelId, aiModel.modelId))
         .where(and(
           eq(generatedImage.isFeatured, true),
           sql`${generatedImage.originalUrl} !~* ${RETIRED_STORAGE_URL_PATTERN}`,