refactor(utils): drop importlib.resources fallback below the 3.11 floor

requires-python is >=3.11, so the ImportError branch that guarded
importlib.resources.files is dead code. Import it at module scope and
keep only the failures files() can really raise.

The python37-compatibility rule still matches the import itself even
though 3.11 has files(). That is a false positive for this floor, so
the import carries a one-line nosemgrep.

src/vocalinux/utils/model_checksums.py

@@ -32,6 +32,7 @@ import logging
 import os
 import re
 from functools import lru_cache
+from importlib.resources import files  # nosemgrep: python37-compatibility-importlib2 -- py>=3.11
 from typing import Dict, NamedTuple, Optional
 
 from ..app_identity import VERIFICATION_STAMP_NAME
@@ -72,10 +73,8 @@ def _manifest_text() -> str:
     :func:`verify_model_file`, which is the safe direction to fail.
     """
     try:
-        from importlib.resources import files
-
         return files(__package__).joinpath(_MANIFEST_NAME).read_text(encoding="utf-8")
-    except (ImportError, TypeError, ModuleNotFoundError):
+    except (TypeError, ModuleNotFoundError):
         pass
     except (FileNotFoundError, OSError):
         return ""