fix(workspace): tolerate read-only files on delete

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

internal/workspace/manager_test.go

@@ -6,6 +6,27 @@ import (
 	"testing"
 )
 
+func TestLocalManagerDeleteRemovesReadOnlyFiles(t *testing.T) {
+	mgr := NewLocalManager(t.TempDir())
+	ws, err := mgr.Create("readonly")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	readonlyFile := filepath.Join(ws.Root, "readonly.txt")
+	if err := os.WriteFile(readonlyFile, []byte("x"), 0o444); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := mgr.Delete("readonly"); err != nil {
+		t.Fatalf("Delete: %v", err)
+	}
+
+	if _, err := os.Stat(ws.Root); !os.IsNotExist(err) {
+		t.Fatalf("workspace root still exists: %v", err)
+	}
+}
+
 func TestLocalManagerListReturnsSortedWorkspaces(t *testing.T) {
 	mgr := NewLocalManager(t.TempDir())
 	if _, err := mgr.Create("beta"); err != nil {