refactor(srp): remove managed frame planning hook

- derive fullscreen stage planning from pipeline render-graph support
- trim planning-only APIs from the managed SRP bridge and public surface
- update probes and tests to lock the slimmer SRP API boundary

managed/XCEngine.ScriptCore/Rendering/Renderer/ScriptableRendererFeature.cs

@@ -20,11 +20,6 @@ namespace XCEngine.Rendering.Renderer
         {
         }
 
-        public virtual void ConfigureCameraFramePlan(
-            ScriptableRenderPipelinePlanningContext context)
-        {
-        }
-
         public virtual void AddRenderPasses(
             ScriptableRenderer renderer,
             RenderingData renderingData)