feat(history): 会话消息持久化 + 主/次级会话（design/16）

- runtime/history: Store + HistoryStore 接口（Append/List 游标分页/Recent/DeleteSession/NewSubSession/ListSessions），主会话固定 web、次级 web:<uuid>
- db 迁移 0003: chat_sessions + chat_messages + idx_chat_msgs_session_created（事务幂等）
- gateway: GET/POST /sessions、GET /sessions/{id}/messages 热分页、DELETE /sessions/{id}（主不可删 403）；Deps.History 可空注入
- 编排层落库: session_persist.go（submitInternal 写用户消息、completeTurn 写助手消息，拒绝的消息不落库）
- WS: wsEvent 加 sessionId 定向 + history 回放帧（握手上行后回放主会话最新 50 条，thinking 剥离）
- wire.go 装配 History 到 gateway.Deps.History
- 端到端实测: POST /sessions 建次级 201 / GET /sessions 列表 / POST /chat 后 /messages 读到 user+assistant / DELETE 次级成功 / DELETE 主会话 403

cmd/cyrene/wire.go

@@ -23,6 +23,7 @@ import (
 	"git.yeij.top/AskaEth/Cyrene_v2/internal/persona/loader"
 	personareg "git.yeij.top/AskaEth/Cyrene_v2/internal/persona/registry"
 	"git.yeij.top/AskaEth/Cyrene_v2/internal/platform"
+	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/history"
 	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/agent"
 	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/capacity"
 	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/embedding"
@@ -92,6 +93,7 @@ type app struct {
 	backthink     *backthink.Backthink
 	vindex        vector.Index
 	owner         *user.OwnerProfile
+	history       *history.Store
 	gw            *gateway.Server
 	channelBridge *channelbridge.Bridge
 }
@@ -510,6 +512,11 @@ func (a *app) wireFrontend() error {
 		a.log.Warn("audit store unavailable, falling back to in-memory", "error", aerr)
 		auditStore = nil
 	}
+	hist, herr := history.NewStore(context.Background(), a.db, a.log)
+	if herr != nil {
+		return fmt.Errorf("history store: %w", herr)
+	}
+	a.history = hist
 	gw, err := gateway.New(a.cfg, gateway.Deps{
 		Log:         logger.WithSource(a.log, "gateway"),
 		Auth:        jwt,
@@ -519,6 +526,7 @@ func (a *app) wireFrontend() error {
 		Session:     a.sessions,
 		Personas:    a.personas,
 		Memories:    a.memStore,
+		History:     a.history,
 		IoT:         a.iot,
 		Scheduler:   a.scheduler,
 		Tasks:       a.tasks,