Git PR Merge

Push the current branch, create a GitHub Pull Request with auto-generated title and body, run a structured review of the diff, wait for CI checks, and squash-merge with explicit user confirmation. Use when the user asks to "open a PR", "create a pull request and merge", "ship this branch", "merge this branch into main", or wants the full push-to-merge workflow. Uses the `gh` CLI; squash-merges by default; never merges without explicit user "yes"; deletes the source branch and switches back to the base branch after merge. Third step of the git-conflict-review → git-conflict-resolve → git-pr-merge workflow; safe to run standalone if the branch is already conflict-free.