Implement ssort

Since Ruff already implements [isort](https://beta.ruff.rs/docs/rules/#isort-i), it would be nice to see [ssort](https://github.com/bwhmather/ssort) implemented as well.

This plugin automatically reorders the contents of a python file so that statements are placed after the things they depend making navigation easier within the file. For example (from the ssort GitHub page):
Before:
```py
from module import BaseClass

def function():
return _dependency()

def _decorator(fn):
return fn

@_decorator
def _dependency():
return Class()

class Class(BaseClass):
def public_method(self):
return self

def __init__(self):
pass
```
After:
```py
from module import BaseClass

class Class(BaseClass):
def __init__(self):
pass

def public_method(self):
return self

def _decorator(fn):
return fn

@_decorator
def _dependency():
return Class()

def function():
return _dependency()
```

Start by reading Ruff's existing isort implementation and the linked ssort project to understand the intended dependency ordering. Use the before-and-after example as the behavioral reference; done means Ruff can reorder Python statements so dependencies and dependent definitions appear in the required order.

Written by the indexing model from the issue text.