Surface outdated gh during repo configure

[codeforester]

Summary

• Add a best-effort Homebrew freshness check for gh during non-dry-run basectl repo configure.
• Warn users to run basectl setup --profile dev when Homebrew reports gh is outdated.
• Cover stale, current, and unavailable Homebrew states in repo configure Bats tests.

Validation

• env BASE_BASH_LIBS_DIR=/Users/rameshhp/work/base-bash-libs/lib/bash bats cli/bash/commands/basectl/tests/repo.bats --filter "warns when Homebrew-managed gh is outdated" (expected failure before implementation)
• env BASE_BASH_LIBS_DIR=/Users/rameshhp/work/base-bash-libs/lib/bash bats cli/bash/commands/basectl/tests/repo.bats --filter "Homebrew-managed gh|gh freshness"
• env BASE_BASH_LIBS_DIR=/Users/rameshhp/work/base-bash-libs/lib/bash bats cli/bash/commands/basectl/tests/repo.bats
• env -u BASE_HOME BASE_BASH_LIBS_DIR=/Users/rameshhp/work/base-bash-libs/lib/bash ./bin/base-test
• git diff --check

Fixes #1047