step 3: add widget shell and renderer foundation

src/dpg_gauges/diagnostics.py

@@ -10,7 +10,7 @@ from .types import Tag
 
 def get_gauge_debug_state(tag: Tag) -> dict[str, Any]:
     state = get_gauge_state(tag)
-    return {
+    debug = {
         "tag": state.tag,
         "gauge_type": state.gauge_type,
         "target_value": state.target_value,
@@ -26,3 +26,6 @@ def get_gauge_debug_state(tag: Tag) -> dict[str, Any]:
         "animation_active": state.animation_state.active,
         "smoothing_active": state.smoothing_state.active,
     }
+    if state.renderer is not None:
+        debug["renderer"] = state.renderer.debug_state()
+    return debug