Add non-maskable PWA icons

It seems Chromium cannot use maskable icons.  It complains that the
"purpose" must contain "any", however maskable icons are not suitable
for the "any" purpose.

So, add pre-masked icons to be used for the "any" purpose.

src/node/routes/vscode.ts

@@ -186,12 +186,22 @@ router.get("/manifest.json", async (req, res) => {
           display: "fullscreen",
           display_override: ["window-controls-overlay"],
           description: "Run Code on a remote server.",
-          icons: [192, 512].map((size) => ({
-            src: `{{BASE}}/_static/src/browser/media/pwa-icon-${size}.png`,
-            type: "image/png",
-            sizes: `${size}x${size}`,
-            purpose: "maskable",
-          })),
+          icons: [192, 512]
+            .map((size) => [
+              {
+                src: `{{BASE}}/_static/src/browser/media/pwa-icon-${size}.png`,
+                type: "image/png",
+                sizes: `${size}x${size}`,
+                purpose: "any",
+              },
+              {
+                src: `{{BASE}}/_static/src/browser/media/pwa-icon-maskable-${size}.png`,
+                type: "image/png",
+                sizes: `${size}x${size}`,
+                purpose: "maskable",
+              },
+            ])
+            .flat(),
         },
         null,
         2,