[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/actions/prepare-bazel-ci/action.yml

@@ -50,7 +50,7 @@ runs:
     - name: Restore bazel repository cache
       id: cache_bazel_repository_restore
       continue-on-error: true
-      uses: actions/cache/restore@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5
+      uses: actions/cache/restore@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
       with:
         path: ${{ steps.setup_bazel.outputs.repository-cache-path }}
         key: ${{ steps.cache_bazel_repository_key.outputs.repository-cache-key }}

.github/actions/windows-code-sign/action.yml

@@ -30,7 +30,7 @@ runs:
   using: composite
   steps:
     - name: Azure login for Trusted Signing (OIDC)
-      uses: azure/login@a457da9ea143d694b1b9c7c869ebb04ebe844ef5 # v2
+      uses: azure/login@a457da9ea143d694b1b9c7c869ebb04ebe844ef5 # v2.3.0
       with:
         client-id: ${{ inputs.client-id }}
         tenant-id: ${{ inputs.tenant-id }}
@@ -54,7 +54,7 @@ runs:
         } >> "$GITHUB_OUTPUT"
 
     - name: Sign Windows binaries with Azure Trusted Signing
-      uses: azure/trusted-signing-action@1d365fec12862c4aa68fcac418143d73f0cea293 # v0
+      uses: azure/trusted-signing-action@1d365fec12862c4aa68fcac418143d73f0cea293 # v0.5.11
       with:
         endpoint: ${{ inputs.endpoint }}
         trusted-signing-account-name: ${{ inputs.account-name }}