refactor: remove dead export_gltf.py, cleanup rendering tasks, improve tessellation UI

- Remove export_gltf.py (Blender-based GLB export replaced by OCC direct)
- Remove unused export_gltf_for_order_line_task
- Add Ultra tessellation preset to Admin settings
- Improve tessellation preset descriptions and styling
- Minor cleanup across media, rendering, and workflow modules

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

backend/app/domains/rendering/tasks.py

@@ -506,52 +506,6 @@ def render_order_line_still_task(self, order_line_id: str, **params) -> dict:
         raise self.retry(exc=exc, countdown=30)
 
 
-@celery_app.task(
-    bind=True,
-    name="app.domains.rendering.tasks.export_gltf_for_order_line_task",
-    queue="asset_pipeline",
-    max_retries=1,
-)
-def export_gltf_for_order_line_task(self, order_line_id: str) -> dict:
-    """Export a geometry GLB directly from STEP via OCC (no STL intermediary).
-
-    Publishes a MediaAsset with asset_type='gltf_geometry'.
-    """
-    import os
-    import subprocess
-    import sys
-
-    step_path_str, cad_file_id = _resolve_step_path_for_order_line(order_line_id)
-    if not step_path_str:
-        raise RuntimeError(f"Cannot resolve STEP path for order_line {order_line_id}")
-
-    step = Path(step_path_str)
-    output_path = step.parent / f"{step.stem}_geometry.glb"
-    scripts_dir = Path(os.environ.get("RENDER_SCRIPTS_DIR", "/render-scripts"))
-    occ_script = scripts_dir / "export_step_to_gltf.py"
-
-    if not occ_script.exists():
-        raise RuntimeError(f"export_step_to_gltf.py not found at {occ_script}")
-
-    try:
-        cmd = [
-            sys.executable, str(occ_script),
-            "--step_path", str(step),
-            "--output_path", str(output_path),
-        ]
-        result = subprocess.run(cmd, capture_output=True, text=True, timeout=120)
-        if result.returncode != 0:
-            raise RuntimeError(
-                f"export_step_to_gltf.py exited {result.returncode}:\n{result.stderr[-500:]}"
-            )
-        publish_asset.delay(order_line_id, "gltf_geometry", str(output_path))
-        logger.info("export_gltf_for_order_line_task completed via OCC: %s", output_path.name)
-        return {"glb_path": str(output_path), "method": "occ"}
-    except Exception as exc:
-        logger.error("export_gltf_for_order_line_task failed for %s: %s", order_line_id, exc)
-        raise self.retry(exc=exc, countdown=15)
-
-
 @celery_app.task(
     bind=True,
     name="app.domains.rendering.tasks.export_blend_for_order_line_task",