feat(release): derive versions from commit history

.github/actions/checkout-release-candidate/action.yml

@@ -0,0 +1,26 @@
+name: Check out release candidate
+description: Materialize the unpushed release commit prepared by the release workflow
+inputs:
+  release-sha:
+    description: Expected release candidate commit
+    required: true
+runs:
+  using: composite
+  steps:
+    - uses: actions/download-artifact@v4
+      with:
+        name: release-candidate
+        path: ${{ runner.temp }}/release-candidate
+    - shell: bash
+      env:
+        RELEASE_SHA: ${{ inputs.release-sha }}
+      run: |
+        git fetch \
+          "$RUNNER_TEMP/release-candidate/release-candidate.bundle" \
+          refs/heads/release-candidate:refs/remotes/release-candidate
+        candidate=$(git rev-parse refs/remotes/release-candidate)
+        if [[ $candidate != "$RELEASE_SHA" ]]; then
+          echo "Release candidate $candidate does not match expected commit $RELEASE_SHA." >&2
+          exit 1
+        fi
+        git checkout --detach "$RELEASE_SHA"

.github/workflows/ci.yml

@@ -5,16 +5,30 @@ on:
     branches:
       - main
   pull_request:
+    types: [opened, edited, synchronize, reopened]
 
 jobs:
   test:
     runs-on: blacksmith-4vcpu-ubuntu-2404
     steps:
+      - name: Validate Conventional Commit title
+        if: github.event_name == 'pull_request'
+        env:
+          PR_TITLE: ${{ github.event.pull_request.title }}
+        shell: bash
+        run: |
+          pattern='^[a-z][a-z0-9-]*(\([^()]+\))?(!)?: .+'
+          if [[ ! $PR_TITLE =~ $pattern ]]; then
+            echo "Pull request titles must use Conventional Commit syntax." >&2
+            echo "Examples: feat: add a feature, fix(api): correct behavior, feat!: break compatibility" >&2
+            exit 1
+          fi
       - uses: useblacksmith/checkout@v1
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: 1.94.0
           components: rustfmt, clippy
+      - run: scripts/tests/test_next_release_version.sh
       - run: cargo fmt --check
       - run: cargo clippy --all-targets --all-features -- -D warnings
       - run: cargo test --locked