Keyboard focus for the diff/review panel (no way to "enter" it)

Problem: When a diff/review ("proposed changes") panel is showing, keystrokes always go to the prompt input. There's no way to move keyboard focus into the diff panel, so its navigation keys (j/k, arrows, space/b, g) never apply unless the panel was opened modally via /diff. If the diff is just displayed alongside the prompt, it can't be driven from the keyboard at all — you have to use the mouse.

Request: A focus-toggle / cycle-pane keybinding (e.g. Tab or Ctrl+O) that moves focus between the prompt and the diff panel, exposed as bindable commands in ~/.claude/keybindings.json (e.g. app:focusDiffPanel / app:focusChat, or a app:cyclePane). Today keybindings.json has DiffDialog / DiffPanel contexts but no focus/cycle command, so it can't be worked around by rebinding.

Environment: Claude Code CLI (terminal).