ci: check pull request titles

Pull requests are squash-merged, so the title becomes the commit on main. A conventional type keeps main's history usable for release notes later.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.gitea/workflows/pr-title.yml

@@ -0,0 +1,40 @@
+name: PR title
+
+# Pull requests are squash-merged, so the title becomes the commit on main:
+# it must start with a conventional commit type, so that release notes can
+# be written from main's history (git-cliff, as lazysecrets does). Brackets
+# and a missing space are fine too.
+#
+#   feat: SOPS and .env files in git repos
+#   fix(search): ctrl+r with empty results loads the scope
+#   feat!: rename config keys          (! marks a breaking change)
+#   [feat] install with a one-liner
+#   [fix]: hide values on blur
+#   docs:split the README
+
+on:
+  pull_request:
+    branches: [main]
+    types: [opened, edited, reopened, synchronize]
+
+jobs:
+  title:
+    name: Conventional title
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check the title
+        env:
+          TITLE: ${{ github.event.pull_request.title }}
+        run: |
+          types='feat|fix|perf|refactor|docs|test|ci|chore|build|style|revert'
+          scope='(\([a-z0-9._/-]+\))?'
+          if [[ "$TITLE" =~ ^\[($types)$scope!?\]!?:?[[:space:]]*(.*)$ ]] ||
+            [[ "$TITLE" =~ ^($types)$scope!?:[[:space:]]*(.*)$ ]]; then
+            what="${BASH_REMATCH[3]}"
+          fi
+          if [[ "${what:-}" =~ [^[:space:]] ]]; then
+            echo "ok: $TITLE"
+          else
+            echo "::error::The title should start with a type, like \"feat: what changed\" or \"[feat] what changed\"; types: ${types//|/, }. Got: $TITLE"
+            exit 1
+          fi