feat: GPU rendering + material matching + perf improvements

- GPU: fix Cycles device activation order — set compute_device_type
  BEFORE engine init, re-set AFTER open_mainfile wipes preferences
- GPU: remove _mark_sharp_and_seams edit-mode loop (redundant with
  Blender 5.0 shade_smooth_by_angle), saves ~200s/render on 175 parts
- Material: fix _AFN suffix mismatch — build AF-stripped mat_map keys
  and add prefix fallback in _apply_material_library (blender_render.py)
- Material: production GLB now uses get_material_library_path() which
  checks active AssetLibrary instead of empty legacy system setting
- Admin: RenderTemplateTable multi-select output types (M2M frontend)
- Admin: MaterialLibraryPanel replaced with link to Asset Libraries
- UX: move Toaster to top-left to avoid dispatch button overlap
- SQLAlchemy: add .unique() to all RenderTemplate M2M collection queries
- Logging: flush=True on all Blender progress prints, stdout reconfigure

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

backend/app/services/step_processor.py

@@ -715,6 +715,7 @@ def render_to_file(
     denoising_prefilter: str = "",
     denoising_quality: str = "",
     denoising_use_gpu: str = "",
+    order_line_id: str | None = None,
 ) -> tuple[bool, dict]:
     """Render a STEP file to a specific output path using current system settings.
 
@@ -734,6 +735,7 @@ def render_to_file(
         target_collection:      Blender collection name to import geometry into.
         material_library_path:  Optional path to material library .blend file.
         material_map:           Optional {part_name: material_name} for material replacement.
+        order_line_id:          Optional order line ID for live log streaming.
 
     Returns:
         (success: bool, render_log: dict)
@@ -819,6 +821,11 @@ def render_to_file(
         if denoising_use_gpu:
             extra["denoising_use_gpu"] = denoising_use_gpu
         from app.services.render_blender import is_blender_available, render_still
+        # Build live-log callback for streaming Blender output to Redis
+        _log_cb = None
+        if order_line_id:
+            from app.services import render_log as _rl
+            _log_cb = lambda line: _rl.emit(order_line_id, line)
         if is_blender_available():
             try:
                 service_data = render_still(
@@ -845,6 +852,7 @@ def render_to_file(
                     denoising_prefilter=denoising_prefilter,
                     denoising_quality=denoising_quality,
                     denoising_use_gpu=denoising_use_gpu,
+                    log_callback=_log_cb,
                 )
                 rendered_png = tmp_png if tmp_png.exists() else None
             except Exception as exc: