Improve Lustre-safe workspace cleanup with dotglob and nullglob

Use shopt dotglob/nullglob for cleaner glob expansion instead of
manual dotfile patterns. Keep retry loop for Lustre ESTALE resilience.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sbryngelson

.github/workflows/bench.yml

@@ -91,13 +91,14 @@ jobs:
       ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION: true
     steps:
       - name: Clean workspace (Lustre-safe)
+        shell: bash
         run: |
+          shopt -s dotglob nullglob
           for i in 1 2 3 4 5; do
-            rm -rf "$GITHUB_WORKSPACE"/pr "$GITHUB_WORKSPACE"/master 2>/dev/null && break
+            rm -rf -- "${GITHUB_WORKSPACE:?}/"* 2>/dev/null && break
             echo "Clean attempt $i failed, retrying in 2s..."
             sleep 2
           done
-          true
 
       - name: Clone - PR
         uses: actions/checkout@v4

.github/workflows/test.yml

@@ -220,13 +220,14 @@ jobs:
       ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION: true
     steps:
       - name: Clean workspace (Lustre-safe)
+        shell: bash
         run: |
+          shopt -s dotglob nullglob
           for i in 1 2 3 4 5; do
-            rm -rf "$GITHUB_WORKSPACE"/{.,}* 2>/dev/null && break
+            rm -rf -- "${GITHUB_WORKSPACE:?}/"* 2>/dev/null && break
             echo "Clean attempt $i failed, retrying in 2s..."
             sleep 2
           done
-          true
 
       - name: Clone
         uses: actions/checkout@v4