v0.19.0

Added

• Add experimental 'gs commit pick' to cherry-pick a commit and update upstack branches in one go. Opt into it with git config --global spice.experiment.commitPick true. The command presents an interactive prompt when invoked without any arguments.
• Add 'gs downstack track' command to track a manually created stack of branches in one go.
• {stack, upstack} restack: prompt for confirmation when invoked from trunk to prevent accidental full-repository restacking. To do this without a prompt, prefer using the gs repo restack command instead.
• submit: Add spice.submit.navigationCommentStyle.marker configuration option to customize the marker in navigation comments

Changed

• branch create: -m/--message now implies --commit
• submit: Warn and prompt for confirmation when submitting branches with zero commits

Fixed

• repo sync: Fix failure to delete merged branches after a sync operation because an upstack branch of the merged branch is checked out in a worktree.