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/lib/creation-text-replay.ts

@@ -0,0 +1,86 @@
+import { appendTaskTextDelta, completeTextReplayTask, createGenerationTask } from "@/services/api/task-center";
+import type { AiConfig } from "@/stores/use-config-store";
+
+/**
+ * text-replay 前端发布器：为前端直连模型生成的文本，在后端维护一个
+ * text_replay 任务作持久化存档 + 回放。
+ *
+ * - start()：创建后端 text_replay 任务（不排队、不计费），拿到 taskId；
+ * - publish(fullText)：按阈值节流地把新增片段通过 appendTaskTextDelta 上报
+ *   （生成中途刷新页面也能读到已生成部分）；
+ * - finish(finalText)：把最终正文写入任务并置为 succeeded，queryTaskTextReplay
+ *   即可读到 finalText。
+ *
+ * 全部失败静默降级：文本直连生成是主流程，后端持久化只是增强，失败不阻塞生成。
+ */
+export function createTextReplayPublisher(config: AiConfig, prompt: string) {
+    let taskId: string | null = null;
+    let lastLen = 0;
+    let buffered = "";
+    let flushTimer: ReturnType<typeof setTimeout> | null = null;
+    let closed = false;
+
+    // 增量累积到该阈值才落一次库，避免逐 token 高频写。
+    const FLUSH_THRESHOLD = 2048;
+    const flush = (force = false) => {
+        if (flushTimer) {
+            clearTimeout(flushTimer);
+            flushTimer = null;
+        }
+        if (closed || !taskId) return;
+        if (buffered.length >= FLUSH_THRESHOLD || force) {
+            const chunk = buffered;
+            buffered = "";
+            if (chunk.trim()) void appendTaskTextDelta(taskId, chunk).catch(() => {});
+        } else if (buffered) {
+            flushTimer = setTimeout(() => flush(true), 1000);
+        }
+    };
+
+    const start = async () => {
+        try {
+            const task = await createGenerationTask({
+                type: "text",
+                prompt: prompt.trim() || "文本创作",
+                model: config.model,
+                input: {
+                    mode: "text",
+                    replay: true,
+                    prompt: prompt.trim() || "文本创作",
+                    config: {
+                        model: config.model,
+                        baseUrl: config.baseUrl,
+                        apiKey: config.apiKey,
+                        apiFormat: config.apiFormat,
+                    },
+                },
+            });
+            taskId = task?.id || null;
+        } catch {
+            taskId = null; // 降级：无持久化，不影响主流程
+        }
+    };
+
+    const publish = (fullText: string) => {
+        if (!taskId) return;
+        if (fullText.length <= lastLen) return;
+        buffered += fullText.slice(lastLen);
+        lastLen = fullText.length;
+        flush();
+    };
+
+    const finish = (finalText: string) => {
+        closed = true;
+        if (flushTimer) {
+            clearTimeout(flushTimer);
+            flushTimer = null;
+        }
+        if (!taskId) return;
+        void appendTaskTextDelta(taskId, buffered).catch(() => {});
+        if (finalText && finalText.trim()) {
+            void completeTextReplayTask(taskId, finalText).catch(() => {});
+        }
+    };
+
+    return { start, publish, finish };
+}

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)));

web/src/services/api/task-center.ts

@@ -391,6 +391,10 @@ export function appendTaskTextDelta(id: string, content: string) {
     return request<TaskTextDelta>(api.post(`/tasks/${encodeURIComponent(id)}/text-deltas`, { content }));
 }
 
+export function completeTextReplayTask(id: string, text: string) {
+    return request<GenerationTask>(api.post(`/tasks/${encodeURIComponent(id)}/text-replay-complete`, { text }));
+}
+
 export function queryTaskTextReplay(id: string, after = 0) {
     return request<TaskTextReplay>(api.get(`/tasks/${encodeURIComponent(id)}/text-deltas`, { params: { after } }));
 }