Gate‑C(Core) OOB strict fail‑fast; String VM handler normalization; JSON lint Stage‑B root fixes via scanner field boxing and BinOp operand slotify; docs + smokes update

src/runtime/mod.rs

@@ -19,6 +19,7 @@ pub mod semantics;
 pub mod unified_registry;
 pub mod provider_lock;
 pub mod provider_verify;
+pub mod observe; // Lightweight observability flags (OOB etc.)
 // pub mod plugin_box;  // legacy - 古いPluginBox
 // pub mod plugin_loader;  // legacy - Host VTable使用
 pub mod extern_registry; // ExternCall (env.*) 登録・診断用レジストリ

src/runtime/observe.rs

@@ -0,0 +1,22 @@
+//! Lightweight execution observability flags used by runner policies
+//! (e.g., Gate‑C(Core) OOB strict fail‑fast).
+
+use std::sync::atomic::{AtomicBool, Ordering};
+
+static OOB_SEEN: AtomicBool = AtomicBool::new(false);
+
+/// Reset all transient observation flags before a run.
+pub fn reset() {
+    OOB_SEEN.store(false, Ordering::Relaxed);
+}
+
+/// Mark that an out‑of‑bounds access was observed in the runtime.
+pub fn mark_oob() {
+    OOB_SEEN.store(true, Ordering::Relaxed);
+}
+
+/// Returns true if an out‑of‑bounds access was observed during the run.
+pub fn oob_seen() -> bool {
+    OOB_SEEN.load(Ordering::Relaxed)
+}
+