Fix search result keyboard navigation

[Ap4sh]

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Description

Fixes #5176

Adds next/previous keyboard navigation for loaded search results, including chats, contacts, and message results

This also wires selected state for message search results, so moving to a message result can highlight the matching row. There was an older PR for this in #5234, but it no longer applies cleanly; this keeps the same issue scoped to current main

Tests:

• pnpm run ready
• targeted electron-mocha for LeftPaneSearchHelper and LeftPaneArchiveHelper: 50 passing