Fix Vite not inserting defined constants in production.

source/ts/components/shared-footer.ts

@@ -7,7 +7,7 @@ export default class SharedFooter extends Component {
     return html`
       <footer class="shared-footer">
         <${ExternalAnchor} text="GitHub" url="https://github.com/Bauke/blink" />
-        <span> v${window.blinkVersion} (${window.blinkCommitHash})</span>
+        <span> v${blinkVersion} (${blinkCommitHash})</span>
       </footer>
     `;
   }

source/ts/types.d.ts

@@ -2,9 +2,7 @@
 export {};
 
 declare global {
-  interface Window {
-    // These are created in `vite.config.ts` and defined by Vite at build time.
-    blinkCommitHash: string;
-    blinkVersion: string;
-  }
+  // These are created in `vite.config.ts` and inserted by Vite at build time.
+  const blinkCommitHash: string;
+  const blinkVersion: string;
 }