fix: Stop mixing stderr into fetched filename list

The 2>&1 on the fetch_files call caused any stderr warnings to be
tokenized as filenames, leading to bogus copy/log entries. Capture
only stdout for filenames and let stderr flow to the terminal.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jcasimir

plugins/compound-engineering/skills/refresh/sync-reviewers.sh

@@ -228,7 +228,7 @@ for (( i=num_sources-1; i>=0; i-- )); do
 
   # Fetch files
   src_tmp=$(mktemp -d)
-  fetched_files=$(fetch_files "$repo" "$branch" "$path" "$src_tmp" 2>&1) || {
+  fetched_files=$(fetch_files "$repo" "$branch" "$path" "$src_tmp") || {
     echo "  Failed to fetch from ${name}. Continuing."
     rm -rf "$src_tmp" "$except_file"
     continue