Add explicit ipywidgets dependency

[jasonhan3]

The problem (described below) is that, when importing tsim in a notebook, we get an error because ipywidgets is not installed.

It would be nice to have either (a) tsim have an extra that installs ipywidgets or (b) to have ipywidgets be a dependency of tsim.

Below is the context of the issue copied from the issue in bloqade-circuit: QuEraComputing/bloqade-circuit#837

With the new version of bloqade-tsim==0.1.4, which no longer installs "ipywidgets" by default, we can an import error from "pyzx_param". However, the error message is masked by the bloqade.tsim ImportError override.

To reproduce

1. Run uv sync --no-dev
2. Run uv pip install bloqade-tsim==0.1.4
3. Run the following code in a notebook

from bloqade.tsim import Circuit
from bloqade import squin

@squin.kernel
def test_kernel():
    reg = squin.qalloc(5)
    return

test_circ = Circuit(test_kernel)

This will yield the following error

---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
Cell In[3], line 1
----> 1 test_circ = Circuit(test_kernel)

File ~/Desktop/qmain/personal-workspace/bloqade-circuit/src/bloqade/tsim/circuit.py:46, in Circuit.__init__(self, kernel, insert_ticks, *args, **kwargs)
     44 if isinstance(kernel, ir.Method):
     45     kernel = _codegen(kernel, insert_ticks=insert_ticks)
---> 46 super().__init__(kernel, *args, **kwargs)

File ~/Desktop/qmain/personal-workspace/bloqade-circuit/src/bloqade/tsim/circuit.py:13, in _MissingTsimCircuit.__init__(self, *args, **kwargs)
     12 def __init__(self, *args, **kwargs):
---> 13     raise ImportError(
     14         "tsim is required for bloqade.tsim.Circuit. "
     15         'Install with: pip install "bloqade-circuit[tsim]"'
     16     )

ImportError: tsim is required for bloqade.tsim.Circuit. Install with: pip install "bloqade-circuit[tsim]"

Issue

The problem is that the user has already installed tsim but the ImportError message says that they should install tsim to fix the problem. The problem is not with installing tsim; the problem can be seen if we import tsim directly. Running the code

from tsim import Circuit

gives the following

---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
Cell In[4], line 1
----> 1 from tsim import Circuit

File ~/Desktop/qmain/personal-workspace/bloqade-circuit/.venv/lib/python3.12/site-packages/tsim/__init__.py:19
      1 """ZX-calculus based circuit sampler for universal quantum circuits.
      2 
      3 tsim supports fast sampling from quantum circuits with few non-Clifford gates.
   (...)     14 - `utils/`: Utility functions for visualization and linear algebra.
     15 """
     17 __version__ = "0.1.4"
---> 19 from tsim.circuit import Circuit as Circuit
     20 from tsim.sampler import (
     21     CompiledDetectorSampler as CompiledDetectorSampler,
     22     CompiledMeasurementSampler as CompiledMeasurementSampler,
     23 )

File ~/Desktop/qmain/personal-workspace/bloqade-circuit/.venv/lib/python3.12/site-packages/tsim/circuit.py:14
      3 from __future__ import annotations
      5 from typing import (
      6     TYPE_CHECKING,
      7     Any,
   (...)     11     overload,
     12 )
---> 14 import pyzx_param as zx
     15 import stim
     16 from pyzx_param.graph.base import BaseGraph

File ~/Desktop/qmain/personal-workspace/bloqade-circuit/.venv/lib/python3.12/site-packages/pyzx_param/__init__.py:48
     46 from . import tikz
     47 from . import simulate
---> 48 from . import editor
     49 from . import routing
     50 from . import local_search

File ~/Desktop/qmain/personal-workspace/bloqade-circuit/.venv/lib/python3.12/site-packages/pyzx_param/editor.py:38
     35 from .editor_actions import MATCHES_VERTICES, MATCHES_EDGES, operations, operations_to_js
     37 if get_mode() == 'notebook':
---> 38 	import ipywidgets as widgets
     39 	from traitlets import Unicode, validate, Bool, Int, Float
     40 	from IPython.display import display, HTML

ModuleNotFoundError: No module named 'ipywidgets'

So the true problem is that the user needs to install 'ipywidgets'.