added versioning

vite.config.ts

@@ -1,6 +1,8 @@
 import path from 'path';
 import { defineConfig, loadEnv } from 'vite';
 import react from '@vitejs/plugin-react';
+import { VitePWA } from 'vite-plugin-pwa';
+import pkg from './package.json';
 
 export default defineConfig(({ mode }) => {
   const env = loadEnv(mode, '.', '');
@@ -9,10 +11,50 @@ export default defineConfig(({ mode }) => {
       port: 3000,
       host: '0.0.0.0',
     },
-    plugins: [react()],
+    plugins: [
+      react(),
+      VitePWA({
+        strategies: 'injectManifest',
+        srcDir: '.',
+        filename: 'sw.ts',
+        registerType: 'autoUpdate',
+        injectRegister: 'auto',
+        devOptions: {
+          enabled: false,
+        },
+        manifest: {
+          name: 'Cognitive Clarity',
+          short_name: 'Clarity',
+          description: 'CBT Case Conceptualization & Roleplay AI',
+          theme_color: '#0f172a',
+          background_color: '#0f172a',
+          display: 'standalone',
+          icons: [
+            {
+              src: 'pwa-192x192.png',
+              sizes: '192x192',
+              type: 'image/png'
+            },
+            {
+              src: 'pwa-512x512.png',
+              sizes: '512x512',
+              type: 'image/png'
+            },
+            {
+              src: 'pwa-512x512.png',
+              sizes: '512x512',
+              type: 'image/png',
+              purpose: 'any maskable'
+            }
+          ]
+        }
+      })
+    ],
     define: {
       'process.env.API_KEY': JSON.stringify(env.VITE_GEMINI_API_KEY),
-      'process.env.GEMINI_API_KEY': JSON.stringify(env.VITE_GEMINI_API_KEY)
+      'process.env.GEMINI_API_KEY': JSON.stringify(env.VITE_GEMINI_API_KEY),
+      '__APP_VERSION__': JSON.stringify(pkg.version),
+      '__BUILD_TIMESTAMP__': JSON.stringify(new Date().toISOString()),
     },
     resolve: {
       alias: {