ci: keep argument comment lint checks materialized (#18926)

## Why

The fast `rust-ci` workflow decides whether to run the cross-platform
`argument-comment-lint` job based on changed paths. PRs that touch
Rust-adjacent Bazel wrapper files, such as `defs.bzl` or
`workspace_root_test_launcher.*.tpl`, can change how Rust tests and lint
targets behave without changing any `.rs` files.

When that detector returned false, GitHub skipped the matrix job before
expanding it. That produced a single skipped check named `Argument
comment lint - ${{ matrix.name }}` instead of the Linux, macOS, and
Windows check names that branch protection expects, leaving the PR
unable to go green when those matrix checks are required.

## What Changed

- Treat root Bazel wrapper files as `argument-comment-lint` relevant
changes.
- Keep the `argument_comment_lint_prebuilt` matrix job materialized for
every PR so the per-platform check names always exist.
- Add a single gate step that decides whether the real lint work should
run.
- Move the checkout-adjacent Bazel setup and OS-specific lint commands
into `.github/actions/run-argument-comment-lint/action.yml` so the
workflow does not repeat the same path-detection condition on each step.

## Verification

- Parsed `.github/workflows/rust-ci.yml` and
`.github/actions/run-argument-comment-lint/action.yml` with Python YAML
loading.
- Simulated the workflow path-matching shell conditions for the root
Bazel wrapper files and confirmed they set `argument_comment_lint=true`.

.github/actions/run-argument-comment-lint/action.yml

@@ -0,0 +1,54 @@
+name: Run argument comment lint
+description: Run argument-comment-lint on codex-rs via Bazel.
+
+inputs:
+  target:
+    description: Runner target passed to setup-bazel-ci.
+    required: true
+  buildbuddy-api-key:
+    description: BuildBuddy API key used by Bazel CI.
+    required: false
+    default: ""
+
+runs:
+  using: composite
+  steps:
+    - uses: ./.github/actions/setup-bazel-ci
+      with:
+        target: ${{ inputs.target }}
+        install-test-prereqs: true
+
+    - name: Install Linux sandbox build dependencies
+      if: ${{ runner.os == 'Linux' }}
+      shell: bash
+      run: |
+        sudo DEBIAN_FRONTEND=noninteractive apt-get update
+        sudo DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends pkg-config libcap-dev
+
+    - name: Run argument comment lint on codex-rs via Bazel
+      if: ${{ runner.os != 'Windows' }}
+      env:
+        BUILDBUDDY_API_KEY: ${{ inputs.buildbuddy-api-key }}
+      shell: bash
+      run: |
+        bazel_targets="$(./tools/argument-comment-lint/list-bazel-targets.sh)"
+        ./.github/scripts/run-bazel-ci.sh \
+          -- \
+          build \
+          --config=argument-comment-lint \
+          --keep_going \
+          --build_metadata=COMMIT_SHA=${GITHUB_SHA} \
+          -- \
+          ${bazel_targets}
+
+    - name: Run argument comment lint on codex-rs via Bazel
+      if: ${{ runner.os == 'Windows' }}
+      env:
+        BUILDBUDDY_API_KEY: ${{ inputs.buildbuddy-api-key }}
+      shell: bash
+      run: |
+        ./.github/scripts/run-argument-comment-lint-bazel.sh \
+          --config=argument-comment-lint \
+          --platforms=//:local_windows \
+          --keep_going \
+          --build_metadata=COMMIT_SHA=${GITHUB_SHA}