feat(create): 创作对话文本模式接入 text-replay 持久化与回放

把后端既有但未接线的 text-replay 能力在前端打通：前端直连模型生成正文时，
把生成过程/结果持久化到后端任务，支持刷新重放与任务中心可见。

后端（最小配套，text-replay 本为前端自管设计）:
- 新增 TaskStatusTextReplay 任务状态：不排入 worker 队列、不计费、不执行，
  仅作为正文增量（text-deltas）的存储容器;
- CreateTask 识别 input.replay=true 的请求，走 createTextReplayTask 轻量创建;
- 新增 POST /tasks/:id/text-replay-complete: 写入最终正文、置为 succeeded、
  触发 text-deltas 归并，使 queryTaskTextReplay 能读到 finalText。

前端:
- 新增 creation-text-replay.ts 发布器: start 建任务、publish 节流上报增量、
  finish 存最终全文，失败静默降级不阻塞生成;
- create 文本模式生成时接入发布器，正文流不经展示改动、额外持久化到后端。

测试: 新增 isTextReplayTaskRequest 纯函数测(本地)、text-replay 闭环仓测
(建任务后写增量 -> complete -> succeeded + finalText，CI/cgo 验证)。
build/vet/tsc 全绿。

web/src/pages/create/index.tsx

@@ -24,6 +24,7 @@ import { isGenerationTaskCancelled, logicalModelIDForConfig, runBackendGeneratio
 import { requestImageQuestion, type AiTextContentPart } from "@/services/api/image";
 import { listAddedSkills, type Skill } from "@/services/api/skills";
 import { cancelGenerationTask, subscribeGenerationTasks, type GenerationTask } from "@/services/api/task-center";
+import { createTextReplayPublisher } from "@/lib/creation-text-replay";
 import { isLocalDreaminaTaskId, isLocalDreaminaWaitStopped, localDreaminaCancellationCopy, localDreaminaCancellationMessage, localDreaminaDetachOutcome } from "@/services/local-dreamina-task-projection";
 import { getMediaBlob, uploadMediaFile } from "@/services/file-storage";
 import { uploadImage } from "@/services/image-storage";
@@ -536,10 +537,18 @@ export default function CreatePage() {
 							? await buildTextMessageContent(item)
 							: item.content,
 					})));
-					await requestImageQuestion(requestConfig, history, (text) => updateOriginAssistant((item) => ({ ...item, content: text })), {
+					const replayPublisher = createTextReplayPublisher(requestConfig, text);
+					void replayPublisher.start();
+					let finalText = "";
+					await requestImageQuestion(requestConfig, history, (full) => {
+						finalText = full;
+						updateOriginAssistant((item) => ({ ...item, content: full }));
+						replayPublisher.publish(full);
+					}, {
 						signal: requestLifecycle.signal,
 						onReasoning: (reasoning) => updateOriginAssistant((item) => ({ ...item, reasoning })),
 					});
+					replayPublisher.finish(finalText);
 				}
             } else if (mode === "image") {
                 const taskCount = Math.max(1, Math.min(imageProfile.maxOutputs, Math.floor(Number(count) || 1)));