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

src/mir/join_ir/lowering/mod.rs

@@ -120,7 +120,7 @@ pub fn is_joinir_if_toplevel_target(name: &str) -> bool {
 ///   - IfMergeTest.* (Phase 33-7)
 ///   - JsonShapeToMap._read_value_from_pair/1 (Phase 33-4 Stage-1)
 ///   - Stage1JsonScannerBox.value_start_after_key_pos/2 (Phase 33-4 Stage-B)
-/// - Requires NYASH_JOINIR_IF_SELECT=1 environment variable
+/// - Requires JoinIR If-select toggle (HAKO_JOINIR_IF_SELECT / joinir_if_select_enabled)
 /// - Falls back to traditional if_phi on pattern mismatch
 ///
 /// Pattern selection:
@@ -138,7 +138,13 @@ pub fn try_lower_if_to_joinir(
     debug: bool,
     context: Option<&if_phi_context::IfPhiContext>, // Phase 61-1: If-in-loop context
 ) -> Option<JoinInst> {
-    // 1. dev トグルチェック
+    // 1. dev/Core トグルチェック
+    //
+    // - Core: joinir_core_enabled() / joinir_if_select_enabled()
+    // - Dev:  joinir_dev_enabled()（詳細ログ等）
+    //
+    // 実際の挙動切り替えは joinir_if_select_enabled() に集約し、
+    // Core/Dev ポリシーは config::env 側で判定する。
     if !crate::config::env::joinir_if_select_enabled() {
         return None;
     }