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>

backend/app/services/step_processor.py

@@ -79,7 +79,7 @@ def match_cad_to_items(
     return matched
 
 
-def extract_cad_metadata(cad_file_id: str) -> None:
+def extract_cad_metadata(cad_file_id: str, tenant_id: str | None = None) -> None:
     """
     Fast metadata extraction for a CAD file (no thumbnail generation).
 
@@ -94,9 +94,11 @@ def extract_cad_metadata(cad_file_id: str) -> None:
     from sqlalchemy import create_engine
     from sqlalchemy.orm import Session
     from app.models.cad_file import CadFile, ProcessingStatus
+    from app.core.tenant_context import set_tenant_context_sync
 
     engine = create_engine(settings.database_url_sync)
     with Session(engine) as session:
+        set_tenant_context_sync(session, tenant_id)
         cad_file = session.get(CadFile, uuid.UUID(cad_file_id))
         if not cad_file:
             logger.error(f"CAD file not found: {cad_file_id}")
@@ -452,6 +454,7 @@ def _get_all_settings() -> dict[str, str]:
         "thumbnail_format":       "jpg",
         "blender_smooth_angle":   "30",
         "cycles_device":          "auto",
+        "tessellation_engine":    "occ",
     }
     try:
         from app.config import settings as app_settings
@@ -533,6 +536,7 @@ def _generate_thumbnail(
                     samples=samples,
                     smooth_angle=int(settings["blender_smooth_angle"]),
                     cycles_device=settings["cycles_device"],
+                    tessellation_engine=settings["tessellation_engine"],
                 )
                 rendered_png = tmp_png if tmp_png.exists() else None
             except Exception as exc:
@@ -642,6 +646,7 @@ def render_to_file(
     denoising_use_gpu: str = "",
     order_line_id: str | None = None,
     usd_path: "Path | None" = None,
+    tessellation_engine: str | None = None,
 ) -> tuple[bool, dict]:
     """Render a STEP file to a specific output path using current system settings.
 
@@ -777,6 +782,7 @@ def render_to_file(
                     denoising_use_gpu=denoising_use_gpu,
                     log_callback=_log_cb,
                     usd_path=usd_path,
+                    tessellation_engine=tessellation_engine or settings["tessellation_engine"],
                 )
                 rendered_png = tmp_png if tmp_png.exists() else None
             except Exception as exc: