Python 3.14 compatibility: magics.py uses type annotation in argparse argument

Description

SQLMesh fails to start on Python 3.14 due to a type annotation being passed to argparse's type parameter in sqlmesh/magics.py.

Error

File ".../sqlmesh/magics.py", line 629, in SQLMeshMagics
    @magic_arguments()
File ".../IPython/core/magic_arguments.py", line 243, in __call__
    func.parser = construct_parser(func)
File ".../argparse.py", line 1548, in add_argument
    raise TypeError(f'{type_func!r} is not callable')
TypeError: bool | typing.Iterable[str] is not callable

Root Cause

In sqlmesh/magics.py around line 635:

@argument(
    "--expand",
    type=t.Union[bool, t.Iterable[str]],  # <-- type annotation, not a callable
    help="...",
)

argparse's type parameter expects a callable function to convert string arguments, not a type annotation. Python 3.14 enforces this more strictly.

Environment

Python: 3.14.2
SQLMesh: 0.228.1
IPython: 9.8.0
OS: macOS

Suggested Fix

Either:

Remove the type parameter (let it be a string)
Use a proper converter function
Use nargs and handle the type conversion in the magic function itself

# Option 1: Remove type, handle in function
@argument("--expand", help="...")

# Option 2: Use a converter function  
def parse_expand(value):
    if value.lower() in ('true', 'false'):
        return value.lower() == 'true'
    return value.split(',')

@argument("--expand", type=parse_expand, help="...")