Improve CI cleanup workflow for macOS runners (#2664)

.github/workflows/nightly-runner-cleanup.yml

-# Nightly disk cleanup for self-hosted macOS CI runners (ci1, ci2).
+# Nightly disk cleanup for self-hosted macOS CI runners.
 # Runs at 4:00 AM PST to prevent disk exhaustion from CI workloads.
 # Safe to run manually via workflow_dispatch for testing.
 
@@ -15,7 +15,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        runner: [ci1, ci2]
+        runner: [ci1, ci2, ci3]
     runs-on: ${{ matrix.runner }}
     steps:
       - name: Checkout (for cleanup script)

scripts/ci-cleanup-macos.sh

@@ -102,14 +102,16 @@ fi
 # 5. npm cache bloat (_cacache, _logs inside ~/.npm)
 # ---------------------------------------------------------------------------
 NPM_CACHE="${HOME}/.npm"
+# npm cache dirs may be locked by concurrent npm processes on shared runners,
+# so these rm -rf calls use || to avoid aborting the script under set -e.
 if [ -d "$NPM_CACHE/_cacache" ]; then
   cache_size=$(du -sh "$NPM_CACHE/_cacache" 2>/dev/null | cut -f1 || echo "?")
   echo "Clearing npm cache (${cache_size})..."
-  rm -rf "$NPM_CACHE/_cacache"
+  rm -rf "$NPM_CACHE/_cacache" 2>/dev/null || echo "Warning: could not fully remove npm cache (likely in use by another process)" >&2
 fi
 if [ -d "$NPM_CACHE/_logs" ]; then
   echo "Removing npm logs"
-  rm -rf "$NPM_CACHE/_logs"
+  rm -rf "$NPM_CACHE/_logs" 2>/dev/null || echo "Warning: could not fully remove npm logs (likely in use by another process)" >&2
 fi
 
 # ---------------------------------------------------------------------------