ExcludeListExtensions disables CustomIgnore functionality

[zx8]

Summary

Setting ExcludeListExtensions completely disables CustomIgnore functionality, making custom ignore files ineffective.

Reproduction Steps

1. Create test files:

mkdir test && cd test
echo "content" >file1.txt
echo "file1.txt" >.customignore

2. Test without ExcludeListExtensions (works):

walker := gocodewalker.NewParallelFileWalker([]string{"."}, fileQueue)
walker.CustomIgnore = []string{".customignore"}
// Result: file1.txt is ignored

3. Test with ExcludeListExtensions (broken):

walker := gocodewalker.NewParallelFileWalker([]string{"."}, fileQueue)
walker.ExcludeListExtensions = []string{"exe", "bin"} // Any value breaks it
walker.CustomIgnore = []string{".customignore"}
// Result: file1.txt is NOT ignored

Expected vs Actual

• Expected: Both settings should work together independently
• Actual: ExcludeListExtensions disables CustomIgnore entirely