test: Disable commit signing in tests

[erezrokah]

Going through the contributing guide and noticed that if you have commit signing enabled (I do) the tests fail.
This PR fixes the issue by disabling it for the relevant tests.

I could also move the logic to a centralized place but that seems premature

[Copilot]

Pull request overview

This PR makes unit tests resilient to developers who have global Git commit signing enabled by explicitly disabling commit.gpgsign inside the temporary repositories created by the tests.

Changes:

• Set git config commit.gpgsign false in initBareWithMetadataBranch to prevent signed commits during strategy tests.
• Disable commit signing in hook_registry_test.go before creating initial commits in two hook-related tests.
• Disable commit signing in explain_test.go’s temporary repo setup to keep the test’s empty commit creation working.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
cmd/entire/cli/strategy/common_test.go	Disables commit signing in the helper that creates commits for metadata-branch tests.
cmd/entire/cli/hook_registry_test.go	Disables commit signing in two tests that create an initial commit as part of repo setup.
cmd/entire/cli/explain_test.go	Disables commit signing in the temp repo initialization used by the explain routing test.

[toothbrush]

Hey @erezrokah, thanks for raising a PR to improve the CLI!

Rather than poking at a specific config flag that breaks tests in this particular situation, i think a better approach would be to ensure Git uses a "clean" config by ignoring any user-configured flags on the system, something like this:

#513

What do you think?