feat: integrate Vite build with unified configuration

- Replace scattered environment variable definitions with unified config
- Use unifiedConfig as primary source for build-time variables
- Maintain backward compatibility with legacy environment variables
- Add proper TypeScript typing for all environment variables
- Include new environment flags: IS_PRODUCTION, IS_DEVELOPMENT
- Simplify configuration management in build process

vite.config.ts

@@ -1,69 +1,75 @@
 import path from 'path';
 import { defineConfig, loadEnv } from 'vite';
+import { unifiedConfig } from './config/unified.config';
 
 export default defineConfig(({ mode }) => {
+  // Still load env for backward compatibility and overrides
   const env = loadEnv(mode, '.', '');
 
+  // Use unified config as the primary source
+  const config = unifiedConfig;
+
   return {
     define: {
       // Legacy API key support
       'process.env.API_KEY': JSON.stringify(env.GEMINI_API_KEY),
       'process.env.GEMINI_API_KEY': JSON.stringify(env.GEMINI_API_KEY),
 
-      // Application configuration
-      'import.meta.env.VITE_APP_NAME': JSON.stringify(
-        env.VITE_APP_NAME || env.APP_NAME || 'RxMinder'
-      ),
-      'import.meta.env.VITE_APP_VERSION': JSON.stringify(
-        env.VITE_APP_VERSION || env.APP_VERSION || '1.0.0'
-      ),
-      'import.meta.env.VITE_BASE_URL': JSON.stringify(
-        env.APP_BASE_URL || env.VITE_BASE_URL || 'http://localhost:5173'
-      ),
+      // Application configuration from unified config
+      'import.meta.env.VITE_APP_NAME': JSON.stringify(config.app.name),
+      'import.meta.env.VITE_APP_VERSION': JSON.stringify(config.app.version),
+      'import.meta.env.VITE_BASE_URL': JSON.stringify(config.app.baseUrl),
 
-      // Database configuration
-      'import.meta.env.VITE_COUCHDB_URL': JSON.stringify(env.VITE_COUCHDB_URL),
+      // Database configuration from unified config
+      'import.meta.env.VITE_COUCHDB_URL': JSON.stringify(config.database.url),
       'import.meta.env.VITE_COUCHDB_USER': JSON.stringify(
-        env.VITE_COUCHDB_USER
+        config.database.username
       ),
       'import.meta.env.VITE_COUCHDB_PASSWORD': JSON.stringify(
-        env.VITE_COUCHDB_PASSWORD
+        config.database.password
       ),
 
-      // Email configuration
+      // Email configuration from unified config
       'import.meta.env.VITE_MAILGUN_API_KEY': JSON.stringify(
-        env.VITE_MAILGUN_API_KEY
+        config.email.mailgun?.apiKey || ''
       ),
       'import.meta.env.VITE_MAILGUN_DOMAIN': JSON.stringify(
-        env.VITE_MAILGUN_DOMAIN
+        config.email.mailgun?.domain || ''
       ),
       'import.meta.env.VITE_MAILGUN_FROM_NAME': JSON.stringify(
-        env.VITE_MAILGUN_FROM_NAME
+        config.email.fromName
       ),
       'import.meta.env.VITE_MAILGUN_FROM_EMAIL': JSON.stringify(
-        env.VITE_MAILGUN_FROM_EMAIL
+        config.email.fromEmail
       ),
 
-      // OAuth configuration
+      // OAuth configuration from unified config
       'import.meta.env.VITE_GOOGLE_CLIENT_ID': JSON.stringify(
-        env.VITE_GOOGLE_CLIENT_ID
+        config.oauth.google?.clientId || ''
       ),
       'import.meta.env.VITE_GITHUB_CLIENT_ID': JSON.stringify(
-        env.VITE_GITHUB_CLIENT_ID
+        config.oauth.github?.clientId || ''
       ),
 
-      // Feature flags
+      // Feature flags from unified config
       'import.meta.env.ENABLE_EMAIL_VERIFICATION': JSON.stringify(
-        env.ENABLE_EMAIL_VERIFICATION !== 'false'
+        config.features.enableEmailVerification
       ),
       'import.meta.env.ENABLE_OAUTH': JSON.stringify(
-        env.ENABLE_OAUTH !== 'false'
+        config.features.enableOAuth
       ),
       'import.meta.env.ENABLE_ADMIN_INTERFACE': JSON.stringify(
-        env.ENABLE_ADMIN_INTERFACE !== 'false'
+        config.features.enableAdminInterface
       ),
-      'import.meta.env.DEBUG_MODE': JSON.stringify(
-        env.DEBUG_MODE === 'true' || mode === 'development'
+      'import.meta.env.DEBUG_MODE': JSON.stringify(config.features.debugMode),
+
+      // Environment info
+      'import.meta.env.NODE_ENV': JSON.stringify(config.app.environment),
+      'import.meta.env.IS_PRODUCTION': JSON.stringify(
+        config.app.environment === 'production'
+      ),
+      'import.meta.env.IS_DEVELOPMENT': JSON.stringify(
+        config.app.environment === 'development'
       ),
     },
     resolve: {