Phase 30.1 & 73: Stage-3 features env and JoinIR flag cleanup

src/mir/join_ir_vm_bridge_dispatch/env_flags.rs

@@ -1,4 +1,4 @@
-use crate::config::env::{joinir_experiment_enabled, joinir_vm_bridge_enabled};
+use crate::config::env::{joinir_core_enabled, joinir_vm_bridge_enabled};
 
 /// JoinIR VM ブリッジの環境フラグ
 #[derive(Debug, Clone, Copy)]
@@ -11,7 +11,7 @@ impl JoinIrEnvFlags {
     /// 現在の環境変数からフラグを取得
     pub fn from_env() -> Self {
         Self {
-            joinir_experiment: joinir_experiment_enabled(),
+            joinir_experiment: joinir_core_enabled(),
             vm_bridge: joinir_vm_bridge_enabled(),
         }
     }