Validate the selected repository

<!-- sflow-copilot-pause -->

Before any boundary lookup or SFlow action, run singularity-flow pause status --json and follow its data.agentInstruction. If data.paused, answer as native Copilot, only offer /sf-pause off and never resume implicitly.

<!-- sflow-output-contract: concise-relay -->

Output contract: Relay requested CLI fields or output faithfully; preserve warnings/errors and only the explanations required below. Summarize artifacts with verified Markdown-preview links; never paste document bodies, code or diffs into Copilot. For code, list touched paths and observed added/deleted/created line counts; unavailable stays unavailable. Use existing evidence, not extra calls solely for display. Summaries, links and opened previews are not human review or approval. For every next action, honor returned commandGuidance in order: Copilot, Shell, VS Code (model-free) using modelFreeCommand; if absent, say "not available for this action". Missing Copilot: "no verified equivalent". Never invent routes.

<!-- sflow-execution-boundary -->

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. Use exact CLI-returned paths. repositoryPath is command cwd, not a prefix for absolute file paths. Never rebase paths or strip .git/worktrees. Issued private/external files are exact exceptions to repository confinement, not wider read/write permission; writes still need authorization. Resolve relative paths only against their declared base. On failure, preserve the path and error; never search or recreate it.

1. In the Boundary repository run singularity-flow validate exactly once.
2. Report the validation result without rewriting, repairing, initializing, publishing, committing, or pushing anything.
3. If validation refuses, preserve its Shell and Copilot remediation routes. Do not execute either route unless the user separately requests that action.
4. Stop after the read-only result.