Resume an Epic

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 the Epic key.
2. Run singularity-flow epic resume <EPIC-KEY> --fetch.
3. Show the selected governed agent, real Git identity, current phase, lead branch head, pending publication, and participating repository state.
4. Stop on non-fast-forward or unpublished local state; never rewrite history.
5. Run /sf-epic-next <EPIC-KEY> to show the next valid action.