Verify or repair branch initialization

Output contract: Let the CLI validate and mutate state; preserve its exact result, warnings, publication status, 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.

Setup only: do not implement, submit, approve, reset, stash, force-push, or edit customizations.

For explicitly requested smart or zero-manual initialization, require a fresh repository:

1. Run singularity-flow init --smart-detect --dry-run --json once. Show stacks, commands, gaps,
   suggestions, write set, and proposal SHA-256. Never run a detected command.
2. Ask explicitly about unresolved candidates and optional protections. Never infer ambiguity or
   select unchecked suggestions.
3. Show --accept-proposal <file> --confirm <sha256>; use --yes only after explicit acceptance.
4. Activate only after exact confirmation. Preserve the receipt, commit, readiness, and next
   command. Proposal-only and review-proposal files are not active law.
5. Run metadata-only singularity-flow precheck --quick --json. Offer Copilot /sf-ready and
   Shell singularity-flow precheck --run --scope dependency-test --json. Only the readiness flow
   (/sf-ready or its shown Shell equivalent)—not init—executes the confirmed repository plan.

On INI_RECOVERY_REQUIRED, run only its exact
singularity-flow init --recover --proposal <SHA256> --json; never edit its journal.

For ordinary init, --check, or --repair, continue with the compatible workflow below.

1. Run singularity-flow init --check --json first. Show branch, completeness, missing files, and
   validation errors.
2. Validate a supplied Work ID as letters, numbers, ., _, or -. If setup/<WORK-ID> is current, use
   singularity-flow init --repair. Otherwise require a clean tree and run
   singularity-flow init --repair --work-id <WORK-ID> --base <BASE> --fetch
   to create, reuse, or fast-forward the setup branch. Never initialize the Story branch itself;
   leave it available for singularity-flow start <WORK-ID> --from-branch setup/<WORK-ID> after setup is committed
   and published. Default to main only for a new setup branch; never modify base.
3. When no Work ID was supplied and the check reports missing assets, run
   singularity-flow init --repair on the current branch.
4. Restore only missing packaged files; never replace customization. Restore invalid files from Git.
5. Rerun singularity-flow init --check --json, then run
   singularity-flow doctor --offline --json. Report every remaining failure
   and warning with its exact fix.
6. Show git status --short and added files. Do not commit or push repair automatically.
7. Before the first Story, offer /sf-ready and
   singularity-flow precheck --run --scope dependency-test --json.

If the initial check is complete, make no changes and say that the branch is
already initialized.