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>

backend/app/api/routers/orders.py

@@ -920,44 +920,17 @@ async def cancel_line_render(
     if line.render_status not in ("processing", "pending"):
         raise HTTPException(400, detail=f"Line render_status is '{line.render_status}', nothing to cancel")
 
-    cancelled_backend = line.render_backend_used or "unknown"
+    cancelled_backend = line.render_backend_used or "celery"
     errors: list[str] = []
 
-    # Cancel Flamenco job if applicable
-    if line.render_backend_used == "flamenco" and line.flamenco_job_id:
-        try:
-            from app.services.flamenco_client import get_flamenco_client
-            from app.models.system_setting import SystemSetting
-            row = await db.execute(
-                select(SystemSetting).where(SystemSetting.key == "flamenco_manager_url")
-            )
-            setting = row.scalar_one_or_none()
-            url = setting.value if setting else "http://flamenco-manager:8080"
-            client = get_flamenco_client(url)
-            client.cancel_job(line.flamenco_job_id)
-        except Exception as exc:
-            errors.append(f"Flamenco cancel failed: {str(exc)[:200]}")
-
-    # Revoke Celery task if applicable
-    if line.render_backend_used == "celery" or not line.render_backend_used:
-        try:
-            from app.tasks.celery_app import celery_app
-            celery_app.control.revoke(
-                f"render-{line_id}", terminate=True, signal="SIGTERM"
-            )
-        except Exception as exc:
-            errors.append(f"Celery revoke failed: {str(exc)[:200]}")
-
-        # Also kill the Blender subprocess in the renderer microservice.
-        # The job_id sent to blender-renderer equals the order_line_id.
-        try:
-            import httpx as _httpx
-            _httpx.post(
-                f"http://blender-renderer:8100/cancel/{line_id}",
-                timeout=5.0,
-            )
-        except Exception:
-            pass  # best-effort; renderer may not be running a job for this line
+    # Revoke Celery task (best-effort)
+    try:
+        from app.tasks.celery_app import celery_app
+        celery_app.control.revoke(
+            f"render-{line_id}", terminate=True, signal="SIGTERM"
+        )
+    except Exception as exc:
+        errors.append(f"Celery revoke failed: {str(exc)[:200]}")
 
     # Mark line as cancelled
     from sqlalchemy import update as sql_update
@@ -1013,47 +986,21 @@ async def cancel_order_renders(
     if not lines:
         raise HTTPException(400, detail="No active renders to cancel")
 
-    from app.services.flamenco_client import get_flamenco_client
-    from app.models.system_setting import SystemSetting
     from app.tasks.celery_app import celery_app
     from sqlalchemy import update as sql_update
 
-    # Load Flamenco URL once
-    row = await db.execute(
-        select(SystemSetting).where(SystemSetting.key == "flamenco_manager_url")
-    )
-    setting = row.scalar_one_or_none()
-    flamenco_url = setting.value if setting else "http://flamenco-manager:8080"
-
     now = datetime.utcnow()
     cancelled_count = 0
     errors: list[str] = []
 
     for line in lines:
-        # Cancel Flamenco job
-        if line.render_backend_used == "flamenco" and line.flamenco_job_id:
-            try:
-                client = get_flamenco_client(flamenco_url)
-                client.cancel_job(line.flamenco_job_id)
-            except Exception as exc:
-                errors.append(f"Line {line.id}: Flamenco cancel failed: {str(exc)[:100]}")
-
-        # Revoke Celery task + kill Blender subprocess in renderer service
-        if line.render_backend_used == "celery" or not line.render_backend_used:
-            try:
-                celery_app.control.revoke(
-                    f"render-{line.id}", terminate=True, signal="SIGTERM"
-                )
-            except Exception:
-                pass  # Celery revoke is best-effort
-            try:
-                import httpx as _httpx
-                _httpx.post(
-                    f"http://blender-renderer:8100/cancel/{line.id}",
-                    timeout=5.0,
-                )
-            except Exception:
-                pass  # best-effort
+        # Revoke Celery task (best-effort)
+        try:
+            celery_app.control.revoke(
+                f"render-{line.id}", terminate=True, signal="SIGTERM"
+            )
+        except Exception:
+            pass
 
         await db.execute(
             sql_update(OrderLine)