feat: save prompt to history when cleared with Ctrl+C

When users press Ctrl+C to clear the input field, the current prompt
is now saved to history before clearing. This allows users to navigate
back to cleared prompts using arrow keys, preventing loss of work.

Addresses #11489

packages/opencode/src/cli/cmd/tui/component/prompt/index.tsx

@@ -832,6 +832,10 @@ export function Prompt(props: PromptProps) {
                   // If no image, let the default paste behavior continue
                 }
                 if (keybind.match("input_clear", e) && store.prompt.input !== "") {
+                  history.append({
+                    ...store.prompt,
+                    mode: store.mode,
+                  })
                   input.clear()
                   input.extmarks.clear()
                   setStore("prompt", {