fix: clear stale pause points when AD VTT is re-uploaded

Old pause_points in edit_state always overrode new VTT cue timings
during re-render, making AD VTT upload for timing adjustments
non-functional. Clear pause_points and video_segments on AD VTT
upload so re-render falls back to the new cue start times.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/api/v1/routes_jobs.py

@@ -1209,6 +1209,14 @@ async def update_job_vtt_content(
         )
         lang_output["ad_vtt_gcs"] = new_ad_uri
 
+        # Clear stale pause points — old positions are invalid with new VTT timings.
+        # Re-render will fall back to VTT cue start_time for placement.
+        edit_state = lang_output.get("accessible_video_edit_state")
+        if edit_state:
+            edit_state["pause_points"] = []
+            edit_state["video_segments"] = []
+            lang_output["accessible_video_edit_state"] = edit_state
+
     # Update job with new VTT content
     outputs[target_language] = lang_output
 

backend/app/tasks/rerender_accessible_video.py

@@ -212,6 +212,8 @@ async def _async_rerender_accessible_video(
             # 4. Build placements with adjusted pause points
             method = lang_output.get("accessible_video_method", "pause_insert")
             pause_points = edit_state.get("pause_points", [])
+            if not pause_points:
+                logger.info("No pause points in edit state — using VTT cue start times for all placements")
 
             placements = _build_placements_with_adjustments(
                 ad_vtt_content, cue_durations, pause_points