pr-precheck

# PR Precheck **Goal:** before you raise a PR, find out whether someone already tried this fix — especially whether anyone tried and got *rejected*. The cost of asking is seconds; the cost of a duplicate PR is reviewer attention, contributor reputation, and (on Bittensor-style mining repos) wasted scoring weight. This skill is a thin orchestration layer over the `vouch pr-cache` CLI shipped in vouch ≥ this PR. It's safe to invoke directly **and** to chain ahead of `pr-fix` / `prs-auto`. ## Invocation Direct: ``` /pr-precheck <repo> <topic-summary> /pr-precheck <repo> <topic-summary> --files a.py,b.py ``` Implicit (auto-fires inside `pr-fix` / `prs-auto` before the "open PR" step): ``` /pr-fix https://github.com/owner/repo/issues/N └─ before pushing the branch, run pr-precheck on the planned PR title + files ``` `<repo>` may be: - `https://github.com/<owner>/<name>` - `git@github.com:<owner>/<name>.git` - `<owner>/<name>` (shorthand) `<topic-summary>` is the title-like phrase that describes the PR you're about to raise. Be specific — short generic strings ("fix bug") will match too many cached PRs. ## Prerequisites - **`vouch` CLI** on `PATH` (`pip install vouch-kb` ≥ the version that ships `pr-cache`). - **`gh` CLI** authenticated for the target repo's read scope (`gh auth status` returns a session). - *Optional:* `claude` CLI on `PATH` **or** `ANTHROPIC_API_KEY` in env — only needed if you pass `--analyze-closed` and want LLM-summarised "why was this closed" n...