Extract repo GitHub settings helper

[codeforester]

Summary

• move basectl repo GitHub-side repository settings, labels, ruleset handling, repo creation, and Project metadata delegation into repo_github_settings.sh
• keep shared path, formatting, gh readiness, PR, and local baseline primitives in repo.sh
• update the repo ownership map and add structural BATS coverage for the new helper boundary

Refs #1563

Validation

• env BASE_BASH_LIBS_DIR=/Users/rameshhp/work/base-bash-libs/lib/bash bats cli/bash/commands/basectl/tests/repo.bats
• bash -n cli/bash/commands/basectl/subcommands/repo.sh cli/bash/commands/basectl/subcommands/repo_github_settings.sh
• shellcheck -S error cli/bash/commands/basectl/subcommands/repo.sh cli/bash/commands/basectl/subcommands/repo_github_settings.sh
• /Users/rameshhp/.base.d/base/.venv/bin/python -m pytest tests/test_base_cli_docs.py tests/test_contract_hardening.py -q
• git diff --check
• env -u BASE_HOME BASE_BASH_LIBS_DIR=/Users/rameshhp/work/base-bash-libs/lib/bash BASE_CACHE_DIR=/private/tmp/base-1563-full ./bin/base-test