Feature: keyboard shortcut to jump between user prompts in transcript view (ctrl+o)

Feature Request

Is your feature request related to a problem?

When scrolling through a long conversation in the transcript view (ctrl+o), there's no way to quickly jump between my previous prompts. In a long session with many tool calls and verbose output, finding a specific earlier prompt requires manual scrolling or relying on terminal search (Cmd+F).

Describe the solution you'd like

A keyboard shortcut (e.g., ctrl+p / ctrl+n or [ / ]) in the transcript view to jump to the previous/next user prompt. This would make it much faster to navigate long conversations.

Describe alternatives you've considered

• Terminal Cmd+F search — works but requires remembering exact text
• Reading the .jsonl transcript file directly — not ergonomic

Additional context

This would be especially useful for long-running sessions with lots of tool calls (e.g., Terraform/infrastructure work) where user prompts are separated by large blocks of tool output.