ci: align Bazel repo cache and Windows clippy target handling (#16740)

## Why

Bazel CI had two independent Windows issues:

- The workflow saved/restored `~/.cache/bazel-repo-cache`, but
`.bazelrc` configured `common:ci-windows
--repository_cache=D:/a/.cache/bazel-repo-cache`, so `actions/cache` and
Bazel could point at different directories.
- The Windows `Bazel clippy` job passed the full explicit target list
from `//codex-rs/...`, but some of those explicit targets are
intentionally incompatible with `//:local_windows`.
`run-argument-comment-lint-bazel.sh` already handles that with
`--skip_incompatible_explicit_targets`; the clippy workflow path did
not.

I also tried switching the workflow cache path to
`D:\a\.cache\bazel-repo-cache`, but the Windows clippy job repeatedly
failed with `Failed to restore: Cache service responded with 400`, so
the final change standardizes on `$HOME/.cache/bazel-repo-cache` and
makes cache restore non-fatal.

## What Changed

- Expose one repository-cache path from
`.github/actions/setup-bazel-ci/action.yml` and export that path as
`BAZEL_REPOSITORY_CACHE` so `run-bazel-ci.sh` passes it to Bazel after
`--config=ci-*`.
- Move `actions/cache/restore` out of the composite action into
`.github/workflows/bazel.yml`, and make restore failures non-fatal
there.
- Save exactly the exported cache path in `.github/workflows/bazel.yml`.
- Remove `common:ci-windows
--repository_cache=D:/a/.cache/bazel-repo-cache` from `.bazelrc` so the
Windows CI config no longer disagrees with the workflow cache path.
- Pass `--skip_incompatible_explicit_targets` in the Windows `Bazel
clippy` job so incompatible explicit targets do not fail analysis while
the lint aspect still traverses compatible Rust dependencies.

## Verification

- Parsed `.github/actions/setup-bazel-ci/action.yml` and
`.github/workflows/bazel.yml` with Ruby's YAML loader.
- Resubmitted PR `#16740`; CI is rerunning on the amended commit.

.github/actions/setup-bazel-ci/action.yml

@@ -9,9 +9,9 @@ inputs:
     required: false
     default: "false"
 outputs:
-  cache-hit:
-    description: Whether the Bazel repository cache key was restored exactly.
-    value: ${{ steps.cache_bazel_repository_restore.outputs.cache-hit }}
+  repository-cache-path:
+    description: Filesystem path used for the Bazel repository cache.
+    value: ${{ steps.configure_bazel_repository_cache.outputs.repository-cache-path }}
 
 runs:
   using: composite
@@ -41,17 +41,16 @@ runs:
     - name: Set up Bazel
       uses: bazelbuild/setup-bazelisk@v3
 
-    # Restore bazel repository cache so we don't have to redownload all the external dependencies
-    # on every CI run.
-    - name: Restore bazel repository cache
-      id: cache_bazel_repository_restore
-      uses: actions/cache/restore@v5
-      with:
-        path: |
-          ~/.cache/bazel-repo-cache
-        key: bazel-cache-${{ inputs.target }}-${{ hashFiles('MODULE.bazel', 'codex-rs/Cargo.lock', 'codex-rs/Cargo.toml') }}
-        restore-keys: |
-          bazel-cache-${{ inputs.target }}
+    - name: Configure Bazel repository cache
+      id: configure_bazel_repository_cache
+      shell: pwsh
+      run: |
+        # Keep the repository cache under HOME on all runners. Windows `D:\a`
+        # cache paths match `.bazelrc`, but `actions/cache/restore` currently
+        # returns HTTP 400 for that path in the Windows clippy job.
+        $repositoryCachePath = Join-Path $HOME '.cache/bazel-repo-cache'
+        "repository-cache-path=$repositoryCachePath" | Out-File -FilePath $env:GITHUB_OUTPUT -Encoding utf8 -Append
+        "BAZEL_REPOSITORY_CACHE=$repositoryCachePath" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
 
     - name: Configure Bazel output root (Windows)
       if: runner.os == 'Windows'
@@ -65,10 +64,6 @@ runs:
         $repoContentsCache = Join-Path $env:RUNNER_TEMP "bazel-repo-contents-cache-$env:GITHUB_RUN_ID-$env:GITHUB_JOB"
         "BAZEL_OUTPUT_USER_ROOT=$bazelOutputUserRoot" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
         "BAZEL_REPO_CONTENTS_CACHE=$repoContentsCache" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
-        if (-not $hasDDrive) {
-          $repositoryCache = Join-Path $env:USERPROFILE '.cache\bazel-repo-cache'
-          "BAZEL_REPOSITORY_CACHE=$repositoryCache" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
-        }
 
     - name: Expose MSVC SDK environment (Windows)
       if: runner.os == 'Windows'