[FEATURE]: TUI: No keyboard shortcut to re-focus input textarea after tmux pane switch #17268

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Describe the enhancement you want to request

When running OpenCode in a tmux pane alongside other panes, switching away and back causes the scrollbox (message area) to have focus instead of the input textarea. j/k scroll works (confirming scrollbox has focus), but there is no keyboard shortcut to move focus back to the input prompt.

The Web/Desktop version has input.focus (Ctrl+L) in use-session-commands.tsx, but the TUI version (dialog-command.tsx command system) does not register an equivalent command.

Workaround: Mouse click on the input area.

Expected: A keybind (e.g. Escape or configurable via tui.json) to return focus to the input textarea from the scrollbox.

Environment: Debian 10, tmux next-3.3, Windows Terminal, OpenCode 1.2.22