wip(0.S2): migrate - a var nothing writes becomes a let; a state is keyed by its module, directory or program, so every program's plan agrees; paths normalized; program states named SceneDemoState / scene_demo_st; the LSP reads state, mut and entry/handler parameters

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

examples/library/input_auto.ludic

@@ -12,11 +12,9 @@ program InputAuto {
   property Tag { n: int = 0 }
   model Player { Tag }
 
-  state InputautoState {
-    hits: int = 0
-  }
+  var hits: int = 0
 
   @OnStart handler Boot { Input.action("go", 'l') }        # 'l' == 108
-  handler Sense(inputauto_st: mut InputautoState) phase Update { if Input.active("go") { inputauto_st.hits += 1 } }
-  @OnQuit handler Report(inputauto_st: InputautoState) { print(inputauto_st.hits) }
+  handler Sense phase Update { if Input.active("go") { hits += 1 } }
+  @OnQuit handler Report { print(hits) }
 }