cleanup: remove dead code and duplicate docs

- Remove session-ses_2f27.md (161KB raw session log)
- Remove 49 ROOT_* duplicate files across REFERENCE/
- Remove 14 duplicate files between REFERENCE/ root and history/
- Remove asr_legacy.rs (dead code, replaced by asr.rs)
- Remove src/core/worker/ (duplicate JobWorker)
- Remove src/core/layers/ (empty directory)
- Remove 4 .bak files in src/
- Remove 7 dead private methods in worker/processor.rs
- Remove backup directory from git tracking

portal/src/api/client.ts

@@ -65,10 +65,11 @@ export interface RegisterResponse {
 export interface UnregisterResponse {
   success: boolean
   message: string
-  file_uuid: string
-  deleted_face_detections: number
-  deleted_processor_results: number
-  deleted_chunks: number
+  file_uuid?: string
+  uuid?: string
+  deleted_face_detections?: number
+  deleted_processor_results?: number
+  deleted_chunks?: number
 }
 
 // ── Config (browser-only, stored in localStorage) ───────────────────────