refactor: strip AI pipeline to binary photo/other classifier

Drops face recognition, OCR, object detection, and semantic embeddings.
The sole remaining vision task is a CLIP-based binary classifier
(photography vs other); photos in "other" get needs_review=true so
screenshots, documents, memes and scans can be triaged from a new
filter pill in the UI.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/services/api.ts

@@ -438,7 +438,6 @@ export interface PipelineStage {
 export interface PipelineStats {
   total_photos: number
   total_images: number
-  embedder_model: string
   stages: PipelineStage[]
 }
 
@@ -621,6 +620,7 @@ export interface LibraryStats {
   with_gps: number
   duplicates: number
   discarded: number
+  needs_review: number
   total_photos: number
   total_videos: number
   total_size: number
@@ -843,7 +843,7 @@ export const sharing = {
 }
 
 // Tags API
-export type TagKind = 'user' | 'object' | 'scene' | 'face_cluster'
+export type TagKind = 'user' | 'content_type'
 
 export interface Tag {
   id: string
@@ -876,11 +876,6 @@ export const tags = {
     await api.delete(`/tags/${tagId}`)
   },
 
-  merge: async (sourceId: string, targetId: string): Promise<{ merged_into: string; target_name: string }> => {
-    const response = await api.post(`/tags/${sourceId}/merge`, { target_id: targetId })
-    return response.data
-  },
-
   /** Add one or more tags to a photo. */
   addToPhoto: async (photoId: string, tagIds: string[]) => {
     const response = await api.post(`/photos/${photoId}/tags`, { tag_ids: tagIds })
@@ -1013,18 +1008,12 @@ export const admin = {
   },
 
   triggerAiBackfill: async (body: {
-    task?: 'embed' | 'ocr' | 'detect' | 'faces' | 'classify' | null
     limit?: number | null
   }): Promise<{ status: string; task_id: string }> => {
     const response = await api.post('/admin/ai/backfill', body)
     return response.data
   },
 
-  triggerFaceRecluster: async (): Promise<{ status: string; task_id: string }> => {
-    const response = await api.post('/admin/ai/recluster-faces')
-    return response.data
-  },
-
   triggerFullRescan: async (): Promise<{ status: string; task_id: string }> => {
     const response = await api.post('/admin/ai/rescan')
     return response.data