feat(M5-M7): embed canonical material names in USD via customData + pxr direct read

- export_step_to_usd.py: accept --material_map CLI arg, write
  schaeffler:canonicalMaterialName as customData on each Mesh prim,
  fix geometry transform (strip shape Location before face exploration,
  apply both face_loc and shape_loc sequentially)
- import_usd.py: after Blender USD import, use pxr to read customData
  directly from the USD file — builds {part_key: material_name} lookup
  (Blender ignores STRING primvars and customData, but pxr reads both)
- _blender_materials.py: add apply_material_library_direct() for exact
  dict-based material assignment without name-matching heuristics
- _blender_scene_setup.py: prefer direct USD lookup, fall back to
  name-matching for legacy USD files without material metadata
- export_glb.py (generate_usd_master_task): resolve material_map via
  material_service.resolve_material_map() and pass to subprocess;
  include material hash in cache key for invalidation
- ROADMAP.md: update P5 status, add M5-M7 milestones

Tested: 3/3 parts matched (ans_lfs120), 172/175 parts matched
(F-802007.TR4-D1-H122AG). Previous: 0/25 matched.

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

render-worker/scripts/_blender_materials.py

@@ -45,17 +45,93 @@ def build_mat_map_lower(material_map: dict) -> dict:
         slug_key = _re.sub(r'[^a-z0-9]+', '_', kl).strip('_')
         if slug_key and slug_key != kl:
             mat_map_lower.setdefault(slug_key, v)
-        # _AF\d+ stripping for GLB object names
-        stripped = kl
-        prev = None
-        while prev != stripped:
-            prev = stripped
-            stripped = _re.sub(r'_af\d+$', '', stripped)
+        # Strip OCC assembly-frame suffixes: _AF0, _AF0_1, _AF0_1_AF0, etc.
+        # Pattern matches one or more groups of _AF<n> optionally followed by
+        # an instance number _<n>, anchored at end of string.
+        stripped = _re.sub(r'(_af\d+(_\d+)?)+$', '', kl)
         if stripped != kl:
             mat_map_lower.setdefault(stripped, v)
+            # Also slug the AF-stripped key for USD path where part_key is
+            # both AF-stripped AND slugified (e.g. "ge360-hf_..." → "ge360_hf_...")
+            slug_stripped = _re.sub(r'[^a-z0-9]+', '_', stripped).strip('_')
+            if slug_stripped and slug_stripped != stripped:
+                mat_map_lower.setdefault(slug_stripped, v)
     return mat_map_lower
 
 
+def apply_material_library_direct(
+    parts: list,
+    mat_lib_path: str,
+    material_lookup: dict[str, str],
+) -> None:
+    """Assign materials from library using a direct object_name → material_name mapping.
+
+    This bypasses all name-matching heuristics — the mapping comes from USD
+    customData (schaeffler:canonicalMaterialName) read via pxr after Blender import.
+    Parts not present in material_lookup receive FAILED_MATERIAL_NAME.
+
+    material_lookup: {blender_object_name: canonical_material_name}
+    """
+    if not mat_lib_path or not os.path.isfile(mat_lib_path):
+        print(f"[blender_render] material library not found: {mat_lib_path}")
+        return
+
+    import bpy  # type: ignore[import]
+
+    # Collect unique material names needed
+    needed = set(material_lookup.values())
+    if not needed:
+        return
+
+    # Append materials from library
+    appended: dict = {}
+    for mat_name in needed:
+        if mat_name in bpy.data.materials:
+            appended[mat_name] = bpy.data.materials[mat_name]
+            continue
+        inner_path = f"{mat_lib_path}/Material/{mat_name}"
+        try:
+            bpy.ops.wm.append(
+                filepath=inner_path,
+                directory=f"{mat_lib_path}/Material/",
+                filename=mat_name,
+                link=False,
+            )
+            if mat_name in bpy.data.materials:
+                appended[mat_name] = bpy.data.materials[mat_name]
+                print(f"[blender_render] appended material: {mat_name}")
+            else:
+                print(f"[blender_render] WARNING: material '{mat_name}' not found after append")
+        except Exception as exc:
+            print(f"[blender_render] WARNING: failed to append material '{mat_name}': {exc}")
+
+    if not appended:
+        return
+
+    assigned_count = 0
+    unmatched_names = []
+    for part in parts:
+        mat_name = material_lookup.get(part.name)
+        if mat_name and mat_name in appended:
+            if part.data.users > 1:
+                part.data = part.data.copy()
+            part.data.materials.clear()
+            part.data.materials.append(appended[mat_name])
+            assigned_count += 1
+        else:
+            unmatched_names.append(part.name)
+
+    print(f"[blender_render] direct material assignment (USD primvars): "
+          f"{assigned_count}/{len(parts)} parts matched", flush=True)
+    if unmatched_names:
+        print(f"[blender_render] unmatched (no primvar): {unmatched_names[:10]}", flush=True)
+        for part in parts:
+            if part.name in set(unmatched_names):
+                if part.data.users > 1:
+                    part.data = part.data.copy()
+                assign_failed_material(part)
+
+
 def apply_material_library(
     parts: list,
     mat_lib_path: str,