Please address the comments from this code review:

## Overall Comments
- In the `trim-go-cache` composite action, consider guarding the `du`, `find`, and `mktemp` calls with a check that `$(go env GOCACHE)` is a non-empty existing directory (similar to the `-d` guard in `cache-go-dependencies`) to avoid accidentally operating on the wrong path when Go or GOCACHE is misconfigured.
- Since `trim-go-cache` relies on `cache-go-dependencies` having run earlier in the job, it may be safer to make that dependency explicit (e.g., by checking for the presence of the year-2000 marker or `trim.txt`) and no-op otherwise, to avoid unexpected deletions if the action is reused in a job without the marking step.

Please address the comments from this code review:

## Overall Comments
- In the post-step trim logic, consider reusing the previously computed `${{ steps.cache-paths.outputs.GOCACHE }}` instead of calling `go env GOCACHE` again to avoid divergence if `GOCACHE` is overridden in the environment.
- The `find ... -exec touch -t 200001010000` over the entire GOCACHE could be expensive on very large caches despite the `timeout 120`; you might want to restrict it (e.g., skip files already older than the cutoff or make the timeout configurable) to avoid rare but pathological runs.

## Individual Comments

### Comment 1
<location path=".github/actions/cache-go-dependencies/action.yaml" line_range="68" />
<code_context>
+          # Go's markUsed() updates mtimes of accessed entries to "now"
+          # (it always updates when mtime is >1 hour old). The post-step
+          # below trims entries still at year 2000 before cache save.
+          timeout 120 find "$gocache" -type f -exec touch -t 200001010000 {} + || true
+          # Protect trim.txt: if backdated, Go's built-in Trim() sees
+          # "last trim was in year 2000" and deletes ALL backdated entries
</code_context>
<issue_to_address>
**issue (bug_risk):** Using `timeout` may break if this composite action is ever run on non-Linux runners.

Composite actions are often reused across workflows with different runners, and `timeout` is only guaranteed on Ubuntu (macOS has `gtimeout`, Windows lacks it). If this is Linux-only, please enforce or document that. Otherwise, consider a portable alternative (e.g., a manual `find` depth/limit strategy or guarding this block by `runner.os`).
</issue_to_address>