Sync repositories with pre-commit guards

Execute guarded repository sync with enforced lint/test gates and dry-run preview

Safe repository synchronization that enforces code quality gates and prevents accidental force pushes

• · current branch state
• · remote tracking info

• · sync preview (dry-run)
• · post-sync repo state (on apply)

• · git (fetch, push, rebase)
• · pre-commit hooks (ruff, ty, unittest, xenon)

• · repo initialized with `gz init`
• · current directory is git worktree

• · divergence blocks sync until resolved
• · lint/test failure blocks until fixed

• · no force push allowed
• · pre-commit hooks mandatory
• · fetch-before-push prevents divergence