[codeforester]

Summary

• Add basectl gh review fetch for detached PR-review worktrees backed by refs/base-review/pr/<number>/<slug>.
• Add basectl gh review prune, dry-run by default, with ownership, cleanliness, detached-state, ref/head, and current PR-state checks before removal.
• Keep legacy local pr-* refs explicitly out of the permanent workflow; they remain a one-time audited cleanup.

Issue

Fixes #2623

Validation

• bats cli/bash/commands/basectl/tests/gh-review.bats
• Full source-checkout BATS suite: 1,067 passed.
• Full Python suite: 1,828 passed.
• Stability, command-reference, and documentation-link checks: 25 passed after enrolling the new stable commands.
• shellcheck cli/bash/commands/basectl/subcommands/gh_review.sh
• git diff --check

Docs Impact

• Updated docs/github-workflow.md, docs/command-reference.md, and the basectl command README.
• Updated Bash/Zsh completions and their parity tests.
• Updated the stable compatibility fixture for the two new public commands.

[codeforester]

Review finding: mismatched review ref is not cleaned up

base_gh_review_fetch compares the fetched commit with the GitHub API head SHA to protect against a force-push between the API read and git fetch. In the mismatch path, the cleanup used the stale API SHA as the git update-ref -d expected old value, even though the namespaced ref already pointed at the fetched commit. That conditional deletion therefore failed and left an orphaned review ref behind.

Impact: a later fetch for the same PR and slug could report that the review checkout already exists, while gh review prune would retain the orphaned ref for manual cleanup.

This is fixed in 09e52e8f: cleanup now uses the ref's actual fetched SHA, and a regression test verifies that both the detached worktree and namespaced ref are removed when the API SHA is stale.