fix(pathfinder): use platform descriptor fields for supported libnames

Prevent import-time failures after the descriptor-catalog refactor by deriving availability from linux/windows descriptor fields instead of removed helpers. Remove an unused catalog-writer variable so pre-commit remains green.

Made-with: Cursor

Author: cpcloud

cuda_pathfinder/cuda/pathfinder/_dynamic_libs/load_nvidia_dynamic_lib.py

@@ -36,7 +36,9 @@
 # All libnames recognized by load_nvidia_dynamic_lib, across all categories
 # (CTK, third-party, driver).
 _ALL_KNOWN_LIBNAMES: frozenset[str] = frozenset(LIB_DESCRIPTORS)
-_ALL_SUPPORTED_LIBNAMES: frozenset[str] = frozenset(name for name, desc in LIB_DESCRIPTORS.items() if desc.sonames)
+_ALL_SUPPORTED_LIBNAMES: frozenset[str] = frozenset(
+    name for name, desc in LIB_DESCRIPTORS.items() if (desc.windows_dlls if IS_WINDOWS else desc.linux_sonames)
+)
 _PLATFORM_NAME = "Windows" if IS_WINDOWS else "Linux"
 
 # Driver libraries: shipped with the NVIDIA display driver, always on the

toolshed/_catalog_writer.py

@@ -166,7 +166,6 @@ def update_specs(
     updates: dict[str, dict[str, object]],
 ) -> tuple[DescriptorSpec, ...]:
     """Apply field updates to matching specs by name, preserving order."""
-    by_name = {spec.name: spec for spec in catalog}
     result = []
     for spec in catalog:
         if spec.name in updates: