[schema-coverage] feat: Add schema coverage demo for check-for-updates field

schema-demos/schema-demo-check-for-updates.md

@@ -0,0 +1,29 @@
+---
+description: Demonstrates the `check-for-updates` schema field
+on:
+  workflow_dispatch:
+permissions:
+  contents: read
+engine: codex
+check-for-updates: false
+timeout-minutes: 5
+---
+
+# Schema Demo: `check-for-updates`
+
+This workflow was auto-generated to demonstrate usage of the `check-for-updates` field in the
+gh-aw frontmatter schema. It exists solely to achieve 100% schema feature coverage.
+
+## What `check-for-updates` Does
+
+Controls whether the compile-agentic version update check runs in the activation job.
+
+## Task
+
+Call `noop` -- this is a coverage-only demo workflow.
+
+**Important**: Always call the `noop` safe-output tool.
+
+```json
+{"noop": {"message": "Coverage demo for `check-for-updates` -- no action needed."}}
+```