refactor(A1): remove Flamenco, simplify render pipeline to Celery-only

- Remove flamenco-manager and flamenco-worker from docker-compose.yml
- Delete flamenco_client.py, flamenco_tasks.py, docker_scaler.py
- Simplify render_dispatcher.py to Celery-only (removes ~300 lines)
- Remove Flamenco beat schedule from celery_app.py
- Clean admin.py: remove flamenco settings, endpoints, threejs validation
- Clean orders.py cancel-render: Celery revoke only
- Clean worker.py: remove flamenco_job_id from activity response
- Migration 032: cancel lingering flamenco jobs, remove flamenco settings
- PLAN.md: mark all decisions confirmed, status IN UMSETZUNG

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

docker-compose.yml

@@ -170,39 +170,6 @@ services:
       - ./threejs-renderer:/app
     restart: unless-stopped
 
-  flamenco-manager:
-    build: ./flamenco
-    environment:
-      - FLAMENCO_MODE=manager
-    ports:
-      - "8080:8080"
-    volumes:
-      - uploads:/shared
-      - flamenco-data:/data
-      - ./flamenco/scripts:/opt/flamenco/scripts
-    restart: unless-stopped
-
-  flamenco-worker:
-    build: ./flamenco
-    environment:
-      - FLAMENCO_MODE=worker
-      - FLAMENCO_MANAGER_URL=http://flamenco-manager:8080
-    volumes:
-      - uploads:/shared
-      - /opt/blender:/opt/blender:ro
-      - ./flamenco/scripts:/opt/flamenco/scripts
-    depends_on:
-      - flamenco-manager
-    deploy:
-      replicas: 1
-      resources:
-        reservations:
-          devices:
-            - driver: nvidia
-              count: 1
-              capabilities: [gpu, compute, utility, graphics]
-    restart: unless-stopped
-
   frontend:
     build:
       context: ./frontend
@@ -220,4 +187,3 @@ services:
 volumes:
   pgdata:
   uploads:
-  flamenco-data: