ci: fix verify.yml structure (valid YAML)

Author: inaciovasquez2020

.github/workflows/verify.yml

@@ -1,6 +1,25 @@
+name: verify
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  verify:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
 
       - name: EntropyDepth invariant guard
         run: |
           test -f docs/ENTROPY_DEPTH_SPEC.md
           test -f docs/REFEREE_OVERVIEW.md
           test -f CONTRIBUTING.md
+
+      - name: Check Chronos constants
+        run: |
+          test -f chronos_constants.json
+          test -f chronos_constants.json.minisig
+          test -f Chronos/Cert/ChronosDepthConstants.lean
+          test -f Chronos/Cert/ChronosDepthConstants.lean.minisig