feat: add phone field to User model and update authentication flow

- Added phone field to User model in Prisma schema and generated types.
- Updated backend authentication to include phone as an additional field.
- Implemented phone input in the signup form with validation.
- Created a new SignupPage component for user registration.
- Updated routing to include signup path and redirect authenticated users.
- Modified login page to reference Playzer and added link to signup.

apps/frontend/src/lib/api-client.ts

@@ -1,10 +1,21 @@
 import { sentinelClient } from '@better-auth/infra/client';
+import { inferAdditionalFields } from 'better-auth/client/plugins';
 import { createAuthClient } from 'better-auth/react';
 import * as api from './api';
 
 const apiBaseUrl = api.apiBaseUrl;
 
-const plugins = [sentinelClient()];
+const plugins = [
+  sentinelClient(),
+  inferAdditionalFields({
+    user: {
+      phone: {
+        type: 'string',
+        required: false,
+      },
+    },
+  }),
+];
 
 export const authClient = createAuthClient({
   baseURL: apiBaseUrl,