Add handle_paste(text) -> ViewAction method to the ModalView trait with a
default no-op. ProviderPickerView overrides it in KeyEntry stage to
sanitize and append pasted text to api_key_input (rejecting whitespace
in the same way as the Char handler).
Wire into the Event::Paste handler in ui.rs: before falling through to
app.insert_paste_text(), check view_stack.handle_paste(). If the top
modal consumes the paste, skip the composer entirely. If a modal is
open but does NOT consume the paste, also skip the composer — any
modal that receives paste while focused should handle it, not leak
into the chat input.
Hunter Bown
42eea19066