feat(kling): add validation error display in timeline panel and update UI components

- Remove unused audio base64 reference and error message in VoiceSelector
- Rename CSS class from 'result-banner' to 'result-inline' and update button styling
- Pass validationError prop from GenerateStep to TimelinePanel
- Add validation error display in TimelinePanel with error state styling
- Update conditional rendering to show either validation error or duration diff
- Add CloseCircleOutlined icon for error status display

frontend/app/web-gold/src/views/kling/IdentifyFace.vue

@@ -850,7 +850,7 @@ onMounted(async () => {
   justify-content: flex-end;
 }
 
-.result-banner {
+.result-inline {
   display: flex;
   align-items: center;
   justify-content: flex-end;
@@ -870,17 +870,7 @@ onMounted(async () => {
     color: @accent-red;
   }
 
-  .banner-icon {
-    font-size: 16px;
-    flex-shrink: 0;
-  }
-
-  .banner-text {
-    flex: 1;
-    text-align: right;
-  }
-
-  .retry-btn {
+  .inline-btn {
     padding: 4px 12px;
     border-radius: 6px;
     border: 1px solid currentColor;
@@ -890,9 +880,6 @@ onMounted(async () => {
     font-weight: 500;
     cursor: pointer;
     transition: all 0.2s ease;
-    display: flex;
-    align-items: center;
-    gap: 4px;
 
     &:hover {
       background: rgba(16, 185, 129, 0.1);