Support CTRL-N/P keyboard navigation in lists

Problem
When tagging conversations, navigating message templates, or browsing other lists, you cannot use CTRL-N and CTRL-P to move through items. You're forced to use arrow keys, which breaks ergonomics for frequent actions.

Request
Support CTRL-N and CTRL-P keyboard shortcuts for navigating up and down in lists, consistent with Chrome, macOS apps, and developer tools.