Import Organization and Standards

This rule applies to files matching the patterns above.

# Import Organization and Standards

## Rule
Imports MUST be organized in three groups separated by blank lines: (1) standard library, (2) third-party, (3) local application. Use absolute imports. Never use wildcard imports.

## Format
```python
# 1. Standard library
import os
import sys
from collections.abc import Sequence
from pathlib import Path

# 2. Third-party packages
import httpx
from fastapi import FastAPI, HTTPException
from pydantic import BaseModel

# 3. Local application
from app.models import User
from app.services.auth import AuthService
```

## Good Examples
```python
from __future__ import annotations

import logging
from datetime import datetime, timedelta
from typing import Any

import sqlalchemy as sa
from fastapi import APIRouter, Depends, HTTPException, status
from pydantic import BaseModel, Field

from app.core.config import settings
from app.core.security import get_current_user
from app.models.user import User
```

## Bad Examples
```python
# BAD: Wildcard import — pollutes namespace
from os.path import *
from django.shortcuts import *

# BAD: No grouping
import os
from app.models import User
import sys
from fastapi import FastAPI
from pathlib import Path

# BAD: Relative imports in application code
from ..models import User        # Use absolute: from app.models import User
from .utils import helper         # Acceptable within packages
```

## Enforcement
- isort or Ruff (I rules) for automatic sorting
- Ruff rule F403 catches wildcard imports
- Configure in pyproject.toml:
```toml
[tool.ruff.isort]
known-first-party = ["app"]
section-order = ["future", "standard-library", "third-party", "first-party", "local-folder"]
```