refactor(runtime): own canonical action state

Move selection, combat, and interaction target mode under one Runtime owner; make plugins, retained UI, session routing, and typed runtime views borrow its exact children; and add failure-safe reset, instance isolation, source ownership, and normalized checkpoint coverage without changing retail ordering.

Co-authored-by: Codex <codex@openai.com>

src/AcDream.Runtime/GameRuntimeViews.cs

@@ -115,6 +115,7 @@ public readonly record struct RuntimeStateCheckpoint(
     RuntimeSocialSnapshot Social,
     long ChatRevision,
     int ChatCount,
+    RuntimeActionSnapshot Actions,
     RuntimeMovementSnapshot Movement,
     RuntimePortalSnapshot Portal);
 
@@ -138,6 +139,8 @@ public interface IGameRuntimeView
 
     IRuntimeChatView Chat { get; }
 
+    IRuntimeActionView Actions { get; }
+
     IRuntimeMovementView Movement { get; }
 
     IRuntimePortalView Portal { get; }