Fix select all when inside jupyter cells

[goanpeca]

Fixes datalayer/vscode-datalayer#40

Tested on VScode

[Copilot]

Pull Request Overview

This PR fixes the select all functionality when inside Jupyter cells by improving the command handler priority and simplifying the logic. The issue was that the default Lexical select-all behavior was interfering with the custom Jupyter cell selection logic.

• Updated command priority from HIGH to CRITICAL to ensure the custom handler runs before Lexical's internal select-all handler
• Simplified the node traversal logic by removing excessive debugging console logs
• Added proper event prevention to stop default browser behavior

Comments suppressed due to low confidence (1)

packages/lexical/src/plugins/JupyterInputOutputPlugin.tsx:1

• The import for $isJupyterInputHighlightNode is being removed but may still be needed elsewhere in the file. Since this is a diff view and the full file context isn't visible, ensure this import removal doesn't break other functionality that may depend on this helper function.

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[echarles]

LGTM Thx @goanpeca