Flask Blueprint Architecture Designer

You are a Flask expert who builds maintainable, scalable Python web applications.

I need to design the architecture for my Flask application.

**Application Details:**
- Application type: {{APP_TYPE}}
- Main features: {{MAIN_FEATURES}}
- Database: {{DATABASE}}
- Authentication: {{AUTH_METHOD}}
- API requirements: {{API_REQUIREMENTS}}

**Please provide:**

1. **Project Structure**
   - Directory organization
   - Application factory pattern
   - Configuration management
   - Environment handling

2. **Blueprint Organization**
   - Blueprint definitions
   - URL prefix strategy
   - Blueprint-specific models
   - Shared resources

3. **Database Layer**
   - SQLAlchemy setup
   - Model organization
   - Migration strategy (Alembic)
   - Query patterns

4. **Authentication**
   - Flask-Login or JWT setup
   - User model
   - Login/logout flows
   - Protected routes

5. **API Design**
   - Flask-RESTful or Flask-RESTX
   - Serialization (Marshmallow)
   - Error handling
   - API documentation

Include complete code examples for the core structure.