docs: add README

Author: zfarrell

README.md

@@ -0,0 +1,22 @@
+# github-workflows
+
+Central repository for organization-wide GitHub Actions workflows enforced across all `hotdata-dev` repos via org rulesets.
+
+## Workflows
+
+### Claude PR Review
+
+Automated code review on every pull request using [claude-code-action](https://github.com/anthropics/claude-code-action). Reviews are severity-based:
+
+- **P0/P1 issues** — requests changes with inline comments
+- **P2/P3 issues** — approves with non-blocking suggestions
+- **No issues** — silent approve
+
+The review prompt lives in [`docs/claude-pr-review-prompt.md`](docs/claude-pr-review-prompt.md).
+
+## Setup
+
+Requires:
+- `ANTHROPIC_API_KEY` org secret
+- [Claude Code GitHub App](https://github.com/apps/claude) installed on the org
+- Org ruleset pointing to this repo's workflow