refactor(task): extract billing and polling logic from controller to service layer

Restructure the task relay system for better separation of concerns:
- Extract task billing into service/task_billing.go with unified settlement flow
- Move task polling loop from controller to service/task_polling.go (supports Suno + video platforms)
- Split RelayTask into fetch/submit paths with dedicated retry logic (taskSubmitWithRetry)
- Add TaskDto, TaskResponse generics, and FetchReq to dto/task.go
- Add taskcommon/helpers.go for shared task adaptor utilities
- Remove controller/task_video.go (logic consolidated into service layer)
- Update all task adaptors (ali, doubao, gemini, hailuo, jimeng, kling, sora, suno, vertex, vidu)
- Simplify frontend task logs to use new TaskDto response format

web/src/components/table/task-logs/TaskLogsColumnDefs.jsx

@@ -396,7 +396,7 @@ export const getTaskLogsColumns = ({
       dataIndex: 'fail_reason',
       fixed: 'right',
       render: (text, record, index) => {
-        // 仅当为视频生成任务且成功，且 fail_reason 是 URL 时显示可点击链接
+        // 视频预览：优先使用 result_url，兼容旧数据 fail_reason 中的 URL
         const isVideoTask =
           record.action === TASK_ACTION_GENERATE ||
           record.action === TASK_ACTION_TEXT_GENERATE ||
@@ -404,14 +404,15 @@ export const getTaskLogsColumns = ({
           record.action === TASK_ACTION_REFERENCE_GENERATE ||
           record.action === TASK_ACTION_REMIX_GENERATE;
         const isSuccess = record.status === 'SUCCESS';
-        const isUrl = typeof text === 'string' && /^https?:\/\//.test(text);
-        if (isSuccess && isVideoTask && isUrl) {
+        const resultUrl = record.result_url;
+        const hasResultUrl = typeof resultUrl === 'string' && /^https?:\/\//.test(resultUrl);
+        if (isSuccess && isVideoTask && hasResultUrl) {
           return (
             <a
               href='#'
               onClick={(e) => {
                 e.preventDefault();
-                openVideoModal(text);
+                openVideoModal(resultUrl);
               }}
             >
               {t('点击预览视频')}

web/src/components/table/task-logs/modals/ContentModal.jsx

@@ -144,8 +144,6 @@ const ContentModal = ({
             maxHeight: '100%',
             objectFit: 'contain',
           }}
-          autoPlay
-          crossOrigin='anonymous'
           onError={handleVideoError}
           onLoadedData={handleVideoLoaded}
           onLoadStart={() => setIsLoading(true)}