T47 Ship: a gallery whose wasm fetch fails retries, then tells the host; the host shows it at once and waits a minute for a slow start

examples/gallery/index.html

@@ -45,7 +45,20 @@
       addEventListener("message", ({ data }) => {
         if (data && data.ely === "theme") setTheme(data.theme);
       });
-      await init();
+      // Frames that fetch the wasm at once can fail one; the next try finds it cached.
+      for (let attempt = 1; ; attempt++) {
+        try {
+          await init();
+          break;
+        } catch (error) {
+          console.warn(`gallery: start failed, try ${attempt}`, error);
+          if (attempt === 3) {
+            window.parent.postMessage({ ely: "failed", error: String(error) }, "*");
+            throw error;
+          }
+          await new Promise((wake) => setTimeout(wake, 1000 * attempt));
+        }
+      }
       apply = set_theme;
       if (early) set_theme(early);
       // Tells the host that a mode it sends now lands.