refactor: rename thumbnail_rendering queue to asset_pipeline

The queue handles far more than thumbnails: OCC tessellation, USD master
generation, GLB production, order line renders, and workflow renders.
asset_pipeline better reflects its role as the render-worker's primary queue.

Updated all references in: task decorators, celery_app.py, beat_tasks.py,
docker-compose.yml worker command, worker.py MONITORED_QUEUES, admin.py,
CLAUDE.md, LEARNINGS.md, Dockerfile, helpTexts.ts, test files,
and all .claude/commands/*.md skill files.

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

docker-compose.yml

@@ -121,7 +121,7 @@ services:
       dockerfile: render-worker/Dockerfile
       args:
         - BLENDER_VERSION=${BLENDER_VERSION:-5.0.1}
-    command: bash -c "python3 /check_version.py && celery -A app.tasks.celery_app worker --loglevel=info -Q thumbnail_rendering --autoscale=1,1 --concurrency=1"
+    command: bash -c "python3 /check_version.py && celery -A app.tasks.celery_app worker --loglevel=info -Q asset_pipeline --autoscale=1,1 --concurrency=1"
     environment:
       - POSTGRES_DB=${POSTGRES_DB:-schaeffler}
       - POSTGRES_USER=${POSTGRES_USER:-schaeffler}