Add inline Other answers to async question choices

[copyberry]

Add inline Other answers to async question choices

Why

Async questions with suggested choices only accepted those choices. Allow users to write an alternative answer directly in the question pane.

What changed

• Append an editable Other choice. Typing or pasting opens it, while number shortcuts still submit named choices.
• Preserve custom drafts when switching choices, reject blank Other submissions, and distinguish the input from a suggested choice named Other.
• Support Vim editing and search in question inputs while keeping arrow keys available for choice navigation.
• Wrap custom answers inline, cap the editor height, and keep the input visible in narrow layouts.

Testing

Add interaction tests and snapshots covering custom answer delivery, draft preservation, selector key repeats, blank answers, remapped shortcuts, Vim editing and search, and narrow or wrapped layouts.

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