docs: add release skill to standardize version bumps

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: GiggleLiu

.claude/CLAUDE.md

@@ -8,6 +8,7 @@ Rust library for NP-hard problem reductions. Implements computational problems w
 - [add-model](skills/add-model.md) -- Add a new problem model. Can be used standalone (brainstorms with user) or called from `issue-to-pr`.
 - [add-rule](skills/add-rule.md) -- Add a new reduction rule. Can be used standalone (brainstorms with user) or called from `issue-to-pr`.
 - [review-implementation](skills/review-implementation.md) -- Review a model or rule implementation for completeness. Auto-detects type from changed files. Called automatically at the end of `add-model`/`add-rule`, or standalone via `/review-implementation`.
+- [release](skills/release.md) -- Create a new crate release. Determines version bump from diff, verifies tests/clippy, then runs `make release`.
 
 ## Commands
 ```bash

.claude/skills/release.md

@@ -0,0 +1,41 @@
+---
+name: release
+description: Use when preparing a new crate release, bumping versions, or tagging a release
+---
+
+# Release
+
+Guide for creating a new release of problemreductions.
+
+## Step 1: Determine Version Bump
+
+Compare against the last release tag:
+
+```bash
+git tag -l 'v0.*' | sort -V          # find latest tag
+git log <last-tag>..HEAD --oneline    # review commits
+git diff <last-tag>..HEAD --stat      # review scope
+```
+
+Apply semver for 0.x (pre-1.0):
+- **Patch** (0.x.Y) — bug fixes, docs, CI only
+- **Minor** (0.X.0) — new features, new reductions, new public API
+- **Major** — reserved for post-1.0
+
+## Step 2: Verify Clean State
+
+```bash
+make test clippy
+```
+
+Both must pass with zero warnings before proceeding.
+
+## Step 3: Release
+
+```bash
+make release V=x.y.z
+```
+
+This target bumps versions in `Cargo.toml` and `problemreductions-macros/Cargo.toml`, runs `cargo check`, commits, tags, and pushes. CI publishes to crates.io.
+
+**Note:** `problemreductions-cli` has its own independent version and is not published to crates.io.