fix: resolve SIGPIPE error in GitHub mirror workflow file cleanup

- Replace problematic 'find | head -20' commands that caused exit code 141
- Use 'ls -la | head -10 || true' for safer file listing
- Add better progress logging during sensitive file removal
- Add error handling with '|| true' to prevent pipe failures

The find command was outputting more than head could handle, causing
SIGPIPE when head closed the pipe early. This fix uses ls which is
more predictable and adds proper error handling.

.gitea/workflows/mirror-to-github.yml

@@ -113,9 +113,11 @@ jobs:
           git checkout github-mirror
           
           echo "Current files before cleanup:"
-          find . -name ".*" -o -name "*" | head -20
+          ls -la | head -10 || true
+          echo "..."
           
           # Remove sensitive files/directories if they exist
+          echo "Removing sensitive files..."
           rm -rf .env* || true
           rm -rf backend/.env* || true
           rm -rf frontend/.env* || true
@@ -136,6 +138,8 @@ jobs:
           rm -rf test-maintenance.sh || true
           rm -rf storage/ || true
           
+          echo "Sensitive files removal completed"
+          
           # Add and commit the cleanup if there are changes
           git add -A
           if ! git diff --cached --quiet; then
@@ -145,8 +149,8 @@ jobs:
             echo "✅ No sensitive files to remove"
           fi
           
-          echo "Final file structure:"
-          find . -name ".*" -o -name "*" | head -20
+          echo "Final file structure (top level):"
+          ls -la | head -10 || true
 
       - name: Verify clean history
         run: |