opencode(run): add queued prompt management (#30103)

Direct run mode previously made submitted follow-up prompts irrevocable while a response was still running. Let users edit or remove queued prompts before dispatch without interrupting the active turn.

packages/opencode/test/cli/run/stream.transport.test.ts

@@ -358,6 +358,7 @@ function footer(fn?: (commit: StreamCommit) => void) {
       return closed
     },
     onPrompt: () => () => {},
+    onQueuedRemove: () => () => {},
     onClose: () => () => {},
     event(next) {
       events.push(next)