fix(web): make first wasm load work on remote deployment

- Correct engine-manifest single wasm SHA and reuse cache for verification.
- Remove duplicate main-thread wasm fetch; raise init timeout to 300s.
- Record production deployment details and verification evidence.

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

web/app/src/app/App.tsx

@@ -43,7 +43,7 @@ import { useCallback, useEffect, useMemo, useReducer, useRef, useState } from "r
 import { createPortal, flushSync } from "react-dom";
 import { WebEngineClient, type BlendOpenResult } from "../engine-client/WebEngineClient";
 import {runEmbeddedRender} from '../engine-client/embedded-render';
-import { loadWebEngineManifest, verifyWasmResource } from "../../../protocol/manifest";
+import { loadWebEngineManifest } from "../../../protocol/manifest";
 import type { ProgressEvent } from "../../../protocol/progress";
 import type { MaterialIR, SceneSnapshotIR } from "../../../protocol/scene-ir";
 import { sequencerCommands } from "../../../protocol/sequencer";
@@ -6050,11 +6050,10 @@ export function App({localOnly=false,course}:{localOnly?:boolean;course?:Availab
   useEffect(() => {
     let mounted = true;
     void loadWebEngineManifest()
-      .then(async (manifest) => {
-        const requiredResource = "variants" in manifest
-          ? manifest.variants.find((variant) => variant.id === "single")?.resources.wasm
-          : manifest.wasm.find((resource) => resource.required);
-        if (requiredResource) await verifyWasmResource(requiredResource);
+      .then((manifest) => {
+        // The engine worker verifies the wasm bytes when it loads the module.
+        // Re-fetching the multi-hundred-MB wasm here doubles the first-load
+        // transfer and can exceed the remote init budget.
         if (mounted) setManifestStatus(`Manifest: verified r${manifest.protocolVersion}`);
       })
       .catch((error: unknown) => {

web/app/src/engine-client/WebEngineClient.ts

@@ -326,7 +326,9 @@ export class WebEngineClient {
   }
 
   async init(): Promise<WebEngineStatus> {
-    return (await this.request({ type: "init" })).status;
+    // The first load fetches and instantiates the multi-hundred-MB engine wasm.
+    // A 30 s budget only fits loopback; remote deployments need a longer first-run window.
+    return (await this.request({ type: "init" }, [], undefined, undefined, undefined, 300_000)).status;
   }
 
   async gpuUICapabilities(): Promise<NonNullable<WebEngineResult["gpuUI"]>> {
@@ -1249,6 +1251,7 @@ export class WebEngineClient {
     onProgress?: (progress: ProgressEvent) => void,
     signal?: AbortSignal,
     nativeInterrupt?: Int32Array,
+    timeoutMs = this.timeoutMs,
   ): Promise<WebEngineResult> {
     if (this.shutdownTask && command.type !== "shutdown" && command.type !== "cancelOpen") return Promise.reject(this.report("INVALID_ARGUMENT", "SESSION_CLOSE_PENDING: native session persistence is in progress", true));
     if (command.type === "openBlend" && signal?.aborted) return Promise.reject(this.report("OPEN_CANCELLED", "Blend open cancelled before dispatch", true));
@@ -1270,7 +1273,7 @@ export class WebEngineClient {
         if (nativeInterrupt && Atomics.load(nativeInterrupt, 0) === 1 && !interruptGraceUsed) {
           interruptGraceUsed = true;
           const pending = this.pending.get(requestId);
-          if (pending) pending.timer = setTimeout(onTimeout, Math.min(this.timeoutMs, 5000));
+          if (pending) pending.timer = setTimeout(onTimeout, Math.min(timeoutMs, 5000));
           return;
         }
         const pending = this.pending.get(requestId);
@@ -1279,9 +1282,9 @@ export class WebEngineClient {
         pending.timedOut = true;
         pending.timeoutError = this.report("WORKER_TERMINATED", `WebEngine 请求超时: ${command.type}`, true);
         pending.cleanup?.(); pending.cleanup = undefined; pending.reject(pending.timeoutError!);
-        pending.timer = setTimeout(() => { if (this.pending.get(requestId) !== pending) return; this.pending.delete(requestId); this.retiredPending.set(requestId, pending); }, this.timeoutMs);
+        pending.timer = setTimeout(() => { if (this.pending.get(requestId) !== pending) return; this.pending.delete(requestId); this.retiredPending.set(requestId, pending); }, timeoutMs);
       };
-      const timer = setTimeout(onTimeout, Math.max(this.timeoutMs,this.renderDeadline-Date.now()));
+      const timer = setTimeout(onTimeout, Math.max(timeoutMs,this.renderDeadline-Date.now()));
       const abort = (): void => {
         void this.request({ type: "cancelOpen", targetRequestId: requestId })
           .catch(() => undefined);