pr-walkthrough

# PR Walkthrough Generate one HTML file that explains why a PR exists and what changes for its users. Lead with the problem, outcome, and compatibility impact. Follow with architecture, code, and trade-offs. This skill is **not** a code-review skill. Do not produce review findings, approve/request-changes verdicts, or a full critique. Explain the change so a reviewer understands it fast. A trusted managed runner supplies a filesystem contract, renders the result, and publishes the HTML. The runner prepares bounded files from the immutable PR head before the agent starts. The agent consumes these files instead of running arbitrary Git or shell commands. The skill never uploads files, changes a pull request, or handles hosting credentials. ## Output You do not write HTML. You write one JSON data file per PR, then run a renderer that builds the HTML: - Data file: `<output-dir>/pr-<number>.json` - HTML page: `<output-dir>/pr-<number>.html` `<output-dir>` is the directory for walkthrough files. The default is `docs/pr-walkthrough/`. The caller may set a different directory. If the host or a CI job gives you an exact path in your instruction, use that path and do not change it. Otherwise use the default and create it if it is missing. `<skill-dir>` is the directory this skill lives in; use it for the `references/` paths in the commands below. For example, PR #12407 writes `pr-12407.json`, and the renderer writes `pr-12407.html`. Never write to a shared `index.html`, and nev...