ci(actions): add Gitea Actions workflow; docs: note CI path in tasks

.gitea/workflows/ci.yml

@@ -0,0 +1,28 @@
+name: CI
+
+on:
+  push:
+    branches: [ "**" ]
+  pull_request:
+    branches: [ "**" ]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build_test_package:
+    runs-on: ubuntu-latest
+    container:
+      image: maven:3.9-eclipse-temurin-17
+    steps:
+      - name: Show Java and Maven versions
+        run: |
+          java -version
+          mvn -v
+      # Gitea act_runner clones the repository; explicit checkout is optional.
+      - name: Build and test
+        run: mvn -B -DskipTests=false clean verify
+      - name: Package
+        run: mvn -B -DskipTests clean package
+