Add Google OAuth authentication infrastructure

- Add passport, passport-google-oauth20, jsonwebtoken, cookie-parser, uuid deps
- Create config/auth.js with JWT, cookie, and OAuth configuration
- Create models/user.js with MongoDB user model and indexes
- Create middleware/passport.js with Google OAuth strategy
- Create middleware/auth.js with requireAuth middleware and sliding window refresh
- Create routes/auth.js with OAuth flow endpoints
- Update server.js to integrate auth, protect all data endpoints (except /health)
- Configure CORS for cookie-based authentication

config/auth.js

@@ -0,0 +1,24 @@
+// Google OAuth and JWT configuration
+module.exports = {
+  google: {
+    clientID: process.env.GOOGLE_CLIENT_ID,
+    clientSecret: process.env.GOOGLE_CLIENT_SECRET,
+    callbackURL: process.env.GOOGLE_CALLBACK_URL,
+    scope: ['profile', 'email']
+  },
+  jwt: {
+    secret: process.env.JWT_SECRET,
+    expiresIn: '7d',
+    refreshThreshold: 24 * 60 * 60  // Refresh if token is older than 1 day (in seconds)
+  },
+  cookie: {
+    name: 'auth_token',
+    options: {
+      httpOnly: true,
+      secure: process.env.NODE_ENV === 'production',
+      sameSite: 'lax',
+      maxAge: 7 * 24 * 60 * 60 * 1000, // 7 days
+      domain: process.env.NODE_ENV === 'production' ? '.maverickapplications.com' : undefined
+    }
+  }
+};