feat(web): preload completed wasm and load debug modules on demand

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

@@ -83,6 +83,17 @@ export class WebEngineClient {
     return (await this.request({ type: "init" })).status;
   }
 
+  async shutdown(): Promise<void> {
+    if (!this.worker) return;
+    try {
+      await this.request({ type: "shutdown" });
+    }
+    finally {
+      this.worker?.terminate();
+      this.worker = null;
+    }
+  }
+
   /** Load one debug WASM module without replacing the completed engine module. */
   async loadDebugWasmModule(id: string): Promise<NonNullable<WebEngineResult["wasmModules"]>> {
     const result = await this.request({ type: "loadWasmModule", id });

web/app/src/engine-client/wasm-module-loader.ts

@@ -37,20 +37,27 @@ export function createWasmModuleLoader(
   const bytes = new Map<string, ArrayBuffer>();
   const statuses = new Map<string, WasmModuleState>(manifest.modules.map((entry) => [entry.id, { id: entry.id, lifecycle: entry.lifecycle, status: "pending", byteLength: 0 }]));
   const loading = new Map<string, Promise<ArrayBuffer>>();
+  const markLoaded = (entry: WasmModuleEntry, value: ArrayBuffer): ArrayBuffer => {
+    statuses.set(entry.id, { id: entry.id, lifecycle: entry.lifecycle, status: "loaded", byteLength: value.byteLength });
+    return value;
+  };
   const load = (entry: WasmModuleEntry): Promise<ArrayBuffer> => {
-    const existing = bytes.get(entry.id);
-    if (existing) return Promise.resolve(existing);
-    const active = loading.get(entry.id);
-    if (active) return active;
-    const promise = fetchVerified(entry.resources[variant], fetcher).then((value) => {
-      bytes.set(entry.id, value);
-      statuses.set(entry.id, { id: entry.id, lifecycle: entry.lifecycle, status: "loaded", byteLength: value.byteLength });
-      return value;
+    const resource = entry.resources[variant];
+    const existing = bytes.get(resource.url);
+    if (existing) return Promise.resolve(markLoaded(entry, existing));
+    const active = loading.get(resource.url);
+    if (active) return active.then((value) => markLoaded(entry, value), (error: unknown) => {
+      statuses.set(entry.id, { id: entry.id, lifecycle: entry.lifecycle, status: "failed", byteLength: 0, error: error instanceof Error ? error.message : String(error) });
+      throw error;
+    });
+    const promise = fetchVerified(resource, fetcher).then((value) => {
+      bytes.set(resource.url, value);
+      return markLoaded(entry, value);
     }).catch((error: unknown) => {
       statuses.set(entry.id, { id: entry.id, lifecycle: entry.lifecycle, status: "failed", byteLength: 0, error: error instanceof Error ? error.message : String(error) });
       throw error;
-    }).finally(() => loading.delete(entry.id));
-    loading.set(entry.id, promise);
+    }).finally(() => loading.delete(resource.url));
+    loading.set(resource.url, promise);
     return promise;
   };
   return {