feat(ci): add actionlint workflow linter

- New workflow that runs actionlint on GitHub workflow file changes
- Runs on push and pull_request events to .github/workflows/**

🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

Author: code-yeongyu

.github/workflows/lint-workflows.yml

@@ -0,0 +1,20 @@
+name: Lint Workflows
+
+on:
+  push:
+    paths:
+      - '.github/workflows/**'
+  pull_request:
+    paths:
+      - '.github/workflows/**'
+
+jobs:
+  actionlint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Run actionlint
+        uses: rhysd/actionlint-action@v1
+        with:
+          fail-on-warning: false