enhancement(deps): surface Restart Kernel and Run All as the primary follow-up action

[captainsafia]

Reported in the March 13, 2026 meeting notes and bug bash feedback.

Current behavior

After dependency changes, the recovery path is buried in the menu instead of being surfaced as the obvious next action.

Requested improvement

When dependencies have changed, promote a primary action like Restart Kernel and Run All instead of leaving the user to discover the right sequence manually.

The bug bash feedback also suggested a split-button treatment, for example:

• Run all cells
• Restart Kernel + Run all
• Restart
• Clear outputs

Notes

One suggestion was to surface this as a larger bottom-right action, but the key request is that the dependency-aware path be much more visible.