Add app version management, update checks, and periodic SW updates

- Introduced version.json and appVersionAssetPlugin for build-time version tracking.
- Enhanced settings page with update check/status UI.
- Refactored bootstrap to handle SW updates and initiate periodic checks.

vite.config.js

@@ -1,10 +1,32 @@
 import { defineConfig } from 'vite';
 import packageJson from './package.json';
 
+function appVersionAssetPlugin() {
+  return {
+    name: 'app-version-asset',
+    apply: 'build',
+    generateBundle() {
+      this.emitFile({
+        type: 'asset',
+        fileName: 'version.json',
+        source: JSON.stringify(
+          {
+            version: packageJson.version,
+            buildTime: new Date().toISOString(),
+          },
+          null,
+          2,
+        ),
+      });
+    },
+  };
+}
+
 export default defineConfig({
   define: {
     __APP_VERSION__: JSON.stringify(packageJson.version),
   },
+  plugins: [appVersionAssetPlugin()],
   server: {
     port: 4173,
   },