Add Go To icon for running cell in Nav

System details:

Positron and OS details:

Positron Version: 2025.10.0 build 26
Code - OSS Version: 1.103.0
Commit: 9ae97b2787cf05db438d025e147ddd587908b559
Date: 2025-09-04T11:21:04.764Z
Electron: 37.2.3
Chromium: 138.0.7204.100
Node.js: 22.17.0
V8: 13.8.500258-electron.0
OS: Darwin arm64 24.6.0

Session details:

R 4.5.0 or Python 3.13.9

Describe the issue:

Spinning 'x' icon when cell execution is halted. Behavior is different from VS Code.

Steps to reproduce the issue:

1. In a Jupyter notebook, attempt to run a script that takes a long time executing, due to number of steps, for example.

%matplotlib inline
import matplotlib.pyplot as plt
import numpy as np
t = np.arange(0,1,0.000000001)
y = np.sin(2*np.pi*t)
plt.plot(t,y)

2. Then, once you notice the cell execution is taking too long, stop the cell execution.
3. Once kernel stops, notice that the icon next to 'Go to' will change from a circular icon to a red x.
4. Mistakenly, that red x icon will be constantly spinning, despite the kernel being stopped. This icon is essentially trying to behave the same way as the other icon that indicates cell is executing. See movie below.

https://github.com/user-attachments/assets/d27422c7-3d8f-46a9-98b4-d6cb5fb26884

Expected or desired behavior:

Just like in VS Code, x icon should be static, NOT spinning.

Design Inspiration

Pycharm

Start by tracing the notebook navigation cell-status icon and reproduce the halt flow with the provided long-running example. Compare the halted-cell icon behavior with the running-cell state and VS Code reference; done means the red x is static after stopping while active execution remains visibly animated.