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```python
# AI Dev Tool: FastAPI Pydantic v2 Micro-SaaS Starter
# ======================================================

"""
Production-ready FastAPI Pydantic v2 Micro-SaaS starter boilerplate.
Includes pre-configured project structure, API routes, and database integration.
"""

# Import dependencies
from fastapi import FastAPI, Depends, HTTPException
from pydantic import BaseModel, Field
from typing import List, Optional
from sqlalchemy import create_engine, Column, Integer, String
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker, Session
from sqlalchemy.exc import SQLAlchemyError

# Initialize FastAPI app
app = FastAPI()

# Define database connection
SQLALCHEMY_DATABASE_URL = "sqlite:///example.db"
engine = create_engine(SQLALCHEMY_DATABASE_URL)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

# Define database models
Base = declarative_base()

class User(Base):
    """User database model."""
    __tablename__ = "users"
    id = Column(Integer, primary_key=True, index=True)
    name = Column(String, unique=True, index=True)
    email = Column(String, unique=True, index=True)

class Item(Base):
    """Item database

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