Enhancement: Allow Customization / Disable Options for Jetpack Shortcut

### Impacted plugin

Jetpack

### What

Add a setting to disable or customize Jetpack’s built-in keyboard shortcuts.

### How

Jetpack currently binds global keyboard shortcuts (e.g., “N” for Notifications) that can interfere with site workflows, especially in interactive or admin-heavy contexts. Users have no way to manage or reassign these shortcuts, and disabling the associated Notifications module appears to be the only workaround.

Suggested improvements:
• Option to disable all or select Jetpack shortcuts
• Option to reassign shortcut keys

This change would improve accessibility and avoid accidental disruptions for users.

The issue does not name implementation files, tests, or entry points. Start by locating Jetpack’s built-in keyboard-shortcut handling and the Notifications module, then determine how shortcut preferences should be represented and exposed. Done means users can disable all or selected shortcuts and reassign keys without disrupting site workflows.

Written by the indexing model from the issue text.