Add a capability boundary

Output contract: Collect every required choice explicitly; never infer or preselect; preserve errors, artifacts, and next actions. For suggested actions, pair Shell with the returned Copilot command; honor commandGuidance. If absent, say "Copilot: no verified equivalent"; never invent a slash command.

Boundary: no Story required; cwd=opened Git root or verified repositoryPath from singularity-flow workspace current --json; refuse if neither resolves; never search $HOME/parents.

1. Require a lower-case kebab-case ID and one repository-relative directory. Accept only a trailing /** shorthand; never accept other glob syntax.
2. Run singularity-flow capability show <DIRECTORY> --json and show the current owner.
3. After the contributor confirms the exact ID and directory, run once:
   singularity-flow capability add <ID> --owns <DIRECTORY> [--name <TEXT>] [--team <TEXT>]... --json.
4. Relay the review branch, commit, receipt, and activation command. Stop; do not review, merge, activate, or hand-edit the map.