feat: Add bulk pipeline reprocessing — creator filter, multi-select, clean retrigger

- Backend: POST /admin/pipeline/clean-retrigger/{video_id} endpoint that
  deletes pipeline_events, key_moments, transcript_segments, and Qdrant
  vectors before retriggering the pipeline
- Backend: QdrantManager.delete_by_video_id() for vector cleanup
- Frontend: Creator filter dropdown on pipeline admin page
- Frontend: Checkbox selection column with select-all
- Frontend: Bulk toolbar with Retrigger Selected and Clean Reprocess
  actions, sequential dispatch with progress bar, cancel support
- Bulk dispatch uses 500ms delay between requests to avoid slamming API

.gsd/STATE.md

@@ -0,0 +1,28 @@
+# GSD State
+
+**Active Milestone:** M011: M011:
+**Active Slice:** None
+**Phase:** complete
+**Requirements Status:** 0 active · 0 validated · 0 deferred · 0 out of scope
+
+## Milestone Registry
+- ✅ **M001:** Chrysopedia Foundation — Infrastructure, Pipeline Core, and Skeleton UI
+- ✅ **M002:** M002:
+- ✅ **M003:** M003:
+- ✅ **M004:** M004:
+- ✅ **M005:** M005:
+- ✅ **M006:** M006:
+- ✅ **M007:** M007:
+- ✅ **M008:** M008:
+- ✅ **M009:** Homepage & First Impression
+- ✅ **M010:** Discovery, Navigation & Visual Identity
+- ✅ **M011:** M011:
+
+## Recent Decisions
+- None recorded
+
+## Blockers
+- None
+
+## Next Action
+All milestones complete.