Fix keyboard shortcuts for shifted punctuation and letters

- Preserve Shift+R semantics for DNS refresh
- Resolve shifted punctuation by produced text across layouts
- Expand keyboard binding coverage tests

tests/test_main.py

@@ -704,7 +704,7 @@ class TestHostsManagerApp:
             for binding in app.BINDINGS:
                 if hasattr(binding, "key"):
                     # Binding object
-                    binding_keys.append(binding.key)
+                    binding_keys.extend(str(binding.key).split(","))
                 elif isinstance(binding, tuple) and len(binding) >= 1:
                     # Tuple format (key, action, description)
                     binding_keys.append(binding[0])