perf: add native hydrate wasm path

tests/native-hydrate-failopen.mjs

@@ -0,0 +1,57 @@
+import assert from "node:assert/strict";
+
+function moduleUrl(tag) {
+  return `../vendor/wasm/stbme_core.js?test=${Date.now()}-${tag}`;
+}
+
+globalThis.__stBmeDisableWasmPackArtifacts = true;
+delete globalThis.__stBmeLoadRustWasmLayout;
+
+const firstLoad = await import(moduleUrl("native-hydrate-first"));
+let firstError = "";
+try {
+  await firstLoad.installNativeHydrateHook();
+} catch (error) {
+  firstError = error?.message || String(error);
+}
+
+assert.match(
+  firstError,
+  /native module unavailable|native hydrate builder unavailable|global-loader|Rust\/WASM artifact is not initialized/i,
+);
+
+globalThis.__stBmeLoadRustWasmLayout = async () => ({
+  solve_layout() {
+    return {
+      ok: true,
+      positions: [],
+      diagnostics: {
+        solver: "mock-rust-wasm",
+      },
+    };
+  },
+  build_hydrate_records() {
+    return {
+      ok: true,
+      usedNative: true,
+      nodes: [],
+      edges: [],
+      diagnostics: {
+        solver: "mock-rust-wasm",
+        nodeCount: 0,
+        edgeCount: 0,
+        recordsNormalized: false,
+      },
+    };
+  },
+});
+
+const retryStatus = await firstLoad.installNativeHydrateHook();
+assert.equal(retryStatus.loaded, true);
+assert.equal(typeof globalThis.__stBmeNativeHydrateSnapshotRecords, "function");
+
+delete globalThis.__stBmeNativeHydrateSnapshotRecords;
+delete globalThis.__stBmeLoadRustWasmLayout;
+delete globalThis.__stBmeDisableWasmPackArtifacts;
+
+console.log("native-hydrate-failopen tests passed");