Regenerate nine utility modules and associated tests with scripts/update_lib
from CPython d220409a13b77de7a6c30abe16ea90db01528edc.
Preserve existing mimetypes fixes by excluding that module from this split.
OpenAI Codex assisted with source audit, update_lib execution, and focused
release validation: 64 tests passed, one existing WASI-only skip.
Assisted-by: OpenAI Codex:model version unavailable