[codex] Fully qualify hash-pins in GitHub Actions (#21436)

This builds on top of https://github.com/openai/codex/pull/15828 by
ensuring that hash-pinned actions with version comments are fully
qualified, rather than referencing floating/mutable comments like "v7".
This makes actions management tools behave more consistently.

This shouldn't break anything, since it's comment only. But if it does,
ping ww@ 🙂

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
       NODE_OPTIONS: --max-old-space-size=4096
     steps:
       - name: Checkout repository
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
       - name: Verify codex-rs Cargo manifests inherit workspace settings
         run: python3 .github/scripts/verify_cargo_workspace_manifests.py
@@ -29,7 +29,7 @@ jobs:
           run_install: false
 
       - name: Setup Node.js
-        uses: actions/setup-node@53b83947a5a98c8d113130e565377fae1a50d02f # v6
+        uses: actions/setup-node@53b83947a5a98c8d113130e565377fae1a50d02f # v6.3.0
         with:
           node-version: 22
 
@@ -63,7 +63,7 @@ jobs:
           echo "pack_output=$PACK_OUTPUT" >> "$GITHUB_OUTPUT"
 
       - name: Upload staged npm package artifact
-        uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7
+        uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
         with:
           name: codex-npm-staging
           path: ${{ steps.stage_npm_package.outputs.pack_output }}