1. 1. Summary

Update `buildscripts/package_test/package_test.py` to use OS-aware package-index update commands and repository setup. For Debian 11, `Test.update_command` disables the expired APT Valid-Until check, and the setup removes the partially pruned `bullseye-security` repository.

Add focused coverage in `buildscripts/tests/test_package_test_commands.py`.

1. 1. Operational benefit

Allows nightly release package tests for Debian 11 to refresh and install packages after Debian 11 repository metadata expired, preventing the recurring `test_packages_release` failure.

1. 1. Safety

The repository and APT option changes are restricted to OS names starting with `debian11`; all other package-test operating systems retain their existing commands.

1. 1. Testing

• `bazel test //buildscripts/tests:test_package_test_commands --test_output=errors`
• `bazel build //buildscripts/package_test:all_python_files`
• `bazel run format`