ci: add Changesets release workflow

.github/workflows/release.yml

@@ -0,0 +1,51 @@
+name: Release
+
+on:
+  push:
+    branches: [main]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+
+jobs:
+  release:
+    name: Version & Publish
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    permissions:
+      contents: write
+      pull-requests: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          # Authenticate git with a PAT (or GitHub App token) rather than the
+          # default GITHUB_TOKEN so the commits the changesets action pushes to
+          # `changeset-release/main` trigger CI. GitHub suppresses workflow runs
+          # on GITHUB_TOKEN-authored pushes (recursion guard), which leaves the
+          # version PR with no required status checks and unmergeable until
+          # someone re-triggers it. Falls back to GITHUB_TOKEN when RELEASE_PAT
+          # isn't configured, so releases keep working regardless.
+          token: ${{ secrets.RELEASE_PAT || secrets.GITHUB_TOKEN }}
+
+      - uses: pnpm/action-setup@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: pnpm
+          registry-url: https://registry.npmjs.org
+
+      - run: pnpm install --frozen-lockfile
+
+      # The `release` script builds packages/* before `changeset publish`.
+      - name: Create Release PR or Publish
+        uses: changesets/action@v1
+        with:
+          title: "chore: version packages"
+          commit: "chore: version packages"
+          version: pnpm changeset:version
+          publish: pnpm release
+        env:
+          GITHUB_TOKEN: ${{ secrets.RELEASE_PAT || secrets.GITHUB_TOKEN }}
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}