Add keyboard shortcut to scroll to previous/next user message in conversation

Feature Request

Currently, Option + ↑/↓ cycles through prompt history at the input line, but there's no way to scroll the conversation view to previous user messages.

Use Case

When working on long conversations, I often need to reference my previous instructions/commands. Currently, I have to manually scroll through all of Claude's responses to find my last message, which is time-consuming.

Proposed Solution

Add keyboard shortcuts (e.g., Cmd + Option + ↑/↓ or Ctrl + Shift + ↑/↓) that scroll the conversation view to the previous/next user message, similar to how IDEs allow jumping between bookmarks or search results.

Alternatives Considered

• Terminal search (Cmd+F) - works but requires typing search text
• /compact - reduces content but loses detail
• iTerm2 triggers - external workaround, not native

This would significantly improve navigation in long sessions.