feat(agent): render local interactive answers and fold completed process

src/features/agent/answer-ui/answer-presentation.ts

@@ -0,0 +1,25 @@
+import type { AgentChatMessage } from "../types";
+import type { AnswerUiPart } from "./contract";
+
+export function getAnswerPresentation(message: AgentChatMessage): {
+  report: AnswerUiPart[];
+  process: AnswerUiPart[];
+  final: boolean;
+} {
+  const parts =
+    message.answerParts ??
+    (message.content ? [{ type: "text" as const, text: message.content }] : []);
+  if (!message.finalAnswer) return { report: parts, process: [], final: false };
+  const selected = new Set(message.finalAnswer.uiBlockIds);
+  const report: AnswerUiPart[] = [{ type: "text", text: message.finalAnswer.content }];
+  for (const id of selected) {
+    const part = parts.find((item) => item.type === "answer-ui" && item.block.block_id === id);
+    if (part) report.push(part);
+  }
+  const process = parts.filter((part) =>
+    part.type === "answer-ui"
+      ? !selected.has(part.block.block_id)
+      : part.text.trim() !== message.finalAnswer!.content.trim()
+  );
+  return { report, process, final: true };
+}