ship

Turn a finished work item into a pull request that GitHub actually links back to its issue. Reads the Work Item Brief for the branch, worktree, contract and issue id, runs /verify-before-done, composes the PR title from the modules the diff really touches, pushes from the tree that holds the commits, opens the PR, then verifies the Closing Link with verify_issue_link.py and performs at most ONE repair. Writes pr:, issue_link: and status: shipped back into the brief. Use when: user says /ship, 'open the PR', 'ship it', 'raise a pull request', or after /verify-before-done passes on a completed item. This is the last stage of the delivery chain.