chat: 持久化继续消息，chat-history 交替历史

基线 main 811912c（PR #125 Muse 风格之后）：服务端与单测与
9538825 相同；React 侧在 Muse 风格 ContinuePanel 上重放
chat-history 集成（新版输入框占位文案保持 Muse 风格的“消息”），
console.html 由新版 src 重新构建。

- 新表 task_continue_messages：POST /continue 的用户消息与状态改回
  queued 同一事务落盘，409 被拒不留 phantom 消息
- GET /tasks/{id}/chat-history：prompt + 继续 + 后续消息 + 链路按
  时间交错拼好返回；部署前继续以 legacy_continue_count 如实标注
- React ContinuePanel 优先用 chat-history，旧服务端自动回退

cloud/console-react/src/api/paths.ts

@@ -38,6 +38,7 @@ export const paths = {
   taskApprovals: (id: string) => "/tasks/" + enc(id) + "/approvals",
   taskApprovalDecision: (id: string, aid: string, verb: string) => "/tasks/" + enc(id) + "/approvals/" + enc(aid) + "/" + verb,
   taskFollowups: (id: string) => "/tasks/" + enc(id) + "/followups",
+  taskChatHistory: (id: string) => "/tasks/" + enc(id) + "/chat-history",
   taskMessages: (id: string) => "/tasks/" + enc(id) + "/messages",
   taskMessagesTo: (target: string) => "/tasks/" + enc(target) + "/messages",
   taskThread: (id: string) => "/tasks/" + enc(id) + "/thread",

cloud/console-react/src/api/types.ts

@@ -17,6 +17,13 @@ export interface Task {
 export interface Review { id: string; target_type?: string; branch?: string; sha?: string; instructions?: string; status?: string; created_at?: number; findings?: string }
 export interface Approval { id: string; kind?: string; status?: string; summary?: string; decision?: string; decided_by?: string; decided_at?: number }
 export interface Followup { mode?: string; status?: string; sender_task_id?: string; body?: string }
+// Chat history from GET /tasks/:id/chat-history: server-merges the task
+// prompt, persisted continue messages, followups and trace entries in
+// timestamp order (see server _task_chat_history). ts_ms is null for
+// trace entries that carried no ts; the server order is authoritative,
+// the client must not re-sort.
+export interface ChatHistoryMessage { id: string; role: "user" | "assistant" | "tool" | "status"; source?: string; label?: string; text: string; ts_ms?: number | null }
+export interface ChatHistory { task_id?: string; status?: string; messages: ChatHistoryMessage[]; continue_messages_stored?: number; legacy_continue_count?: number | null; trace_note?: string }
 export interface PeerMessage { task_id?: string; mode?: string; status?: string; body?: string }
 export interface Automation { id: string; name?: string; status?: string; due?: boolean; interval_seconds?: number; next_run_at?: number }
 export interface Member { user_id: string; username?: string; role?: string }