Build a User Registration and Profile API

Problem/Feature Description

Build a Spring Boot REST API for user registration and profile management. Use Spring Boot 3 and Java 17+.

Domain concepts:

• User: id, email (unique), displayName, passwordHash, role (USER/ADMIN), createdAt, lastLoginAt
• Profile: id, userId, bio, avatarUrl, location, website

Endpoints:

• POST /api/auth/register -- register a new user (email, displayName, password). Email must be unique. Password must be at least 8 characters.
• POST /api/auth/login -- authenticate user (email, password), return a success response
• GET /api/users/:id/profile -- get user profile (public info only: displayName, bio, avatarUrl, location)
• PUT /api/users/:id/profile -- update profile (bio, avatarUrl, location, website)
• GET /api/admin/users -- list all users (admin only, includes email and role but not passwordHash)

Business rules:

• Email must be unique and valid format
• Password is stored hashed (use BCrypt)
• Profile is created automatically when a user registers
• Public profile endpoint must never expose email or passwordHash
• Admin endpoint returns different fields than public profile

Use PostgreSQL for the database.

Output Specification

Produce a complete Spring Boot project with:

• Main application class
• All Java source files
• Spring Security configuration for the auth endpoints
• Configuration files
• Database schema
• Test classes for registration validation and profile retrieval
• pom.xml with dependencies

You may create additional files as needed.