Add new page module and services; refactor existing entities

- Introduced a new page module with associated services.
- Refactored TypeORM entities in user and workspace modules.

server/src/core/core.module.ts

@@ -2,8 +2,9 @@ import { Module } from '@nestjs/common';
 import { UserModule } from './user/user.module';
 import { AuthModule } from './auth/auth.module';
 import { WorkspaceModule } from './workspace/workspace.module';
+import { PageModule } from './page/page.module';
 
 @Module({
-  imports: [UserModule, AuthModule, WorkspaceModule],
+  imports: [UserModule, AuthModule, WorkspaceModule, PageModule],
 })
 export class CoreModule {}