[FEATURE] Expose transcript prompt-jump ({ / }) as a bindable action for non-US keyboard layouts

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• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

The transcript viewer (Ctrl+O) supports jumping between user prompts with { and } (the feature added in #16784). However, those keys are hardcoded and not exposed in the rebindable action registry used by ~/.claude/keybindings.json.

This makes prompt navigation effectively unusable on non‑US keyboard layouts. On a Czech layout (and many other European layouts), { and } are AltGr combinations (AltGr+B / AltGr+N), which are unreliable or simply don't reach the TUI in many terminals. Because there is no corresponding action name, there is no way to remap the jump to keys that the layout can actually produce.

For comparison, scrolling in the transcript (scroll:lineUp, scroll:lineDown, scroll:top, etc.) is exposed and rebindable — only the prompt-jump is not.

Proposed Solution

Expose the prompt-jump in the keybindings action registry so it can be rebound like other transcript actions, e.g.:

• transcript:previousPrompt (default: {)
• transcript:nextPrompt (default: })

This would let users on non‑US layouts do, for example:

{
  "context": "Transcript",
  "bindings": {
    "shift+p": "transcript:previousPrompt",
    "shift+n": "transcript:nextPrompt"
  }
}

Defaults stay exactly as they are today ({ / }), so nothing changes for US-layout users.

Alternative Solutions

• Add additional default bindings that don't require AltGr on common layouts (e.g. [/] are already used for other things, so plain-ASCII alternatives would need care) — but exposing the action and letting users choose is cleaner and more general.
• Document the AltGr workaround — doesn't solve the terminals where AltGr combos never reach the app.

Priority

Low/Medium — small change, but a real accessibility gap for non‑US keyboard users.

Feature Category

Configuration and settings

Use Case Example

Czech layout on a physical US keyboard, Ghostty + Claude Code on macOS. The user wants to re-read a long response from where their prompt started. {/} can't be typed reliably, and there's no action to bind to reachable keys, so the #16784 feature is inaccessible to them. Exposing transcript:previousPrompt / transcript:nextPrompt would let them bind Shift+P / Shift+N (or any reachable keys) and use the feature.

Additional Context

Verified on Claude Code 2.1.150 (latest at time of writing). The action list available to keybindings.json includes transcript:toggleShowAll, transcript:exit, and the scroll:* family, but no prompt-prev/next action. #16784 (closed completed 2026-05-12) added the {/} behavior but did not register it as a bindable action.