add sandboxed NotebookEdit tool for Jupyter notebook editing

[yai-dev]

Summary

Add a sandboxed NotebookEdit tool for cell-level editing of Jupyter notebooks.

Background

Editing .ipynb files through generic text replacement is brittle because notebook content is JSON-encoded, cell indices matter, and code-cell outputs typically need cleanup after edits.

Proposed API

This should target the current sandbox/capability layout rather than a non-existent standalone sandbox package.

Suggested landing area:

• packages/capabilities/src/sandbox/tools/sandboxed-notebook-edit.ts

Suggested factory shape:

export function createSandboxedNotebookEdit(...): RuntimeTool

Operations

• insert
• replace
• delete

Semantics to Pin Down

• preserve existing notebook/cell metadata unless explicitly overwritten
• clear outputs and reset execution state on code-cell replace
• keep notebook JSON round-trippable without lossy rewrites

Acceptance Criteria

• Sandboxed notebook edit tool is exported through the current capability package
• Insert / replace / delete operations are supported
• Replacing a code cell clears outputs safely
• Notebook JSON round-trips without data loss
• Unit tests cover all operations and metadata preservation