refactor(task): replace init registration with bootstrap wiring

Introduce internal/bootstrap as the composition root with sync.Once
guards for task handler registration and push listener wiring. Replace
the single OnTaskCompleted global hook with multi-subscriber handlers
and remove init()-driven side effects from worker, admin task, and push.

internal/apps/admin/push/task_listener.go

@@ -15,8 +15,9 @@ import (
 	"github.com/Rain-kl/Wavelet/pkg/logger"
 )
 
-func init() {
-	task.OnTaskCompleted = handleTaskCompleted
+// RegisterTaskListeners subscribes push notification handlers to task completion events.
+func RegisterTaskListeners() {
+	task.OnTaskCompleted(handleTaskCompleted)
 }
 
 // handleTaskCompleted handles task completions and triggers appropriate push events.

internal/apps/admin/task/routers.go

@@ -13,7 +13,6 @@ import ("fmt"
 	"github.com/Rain-kl/Wavelet/internal/apps/admin"
 	"github.com/Rain-kl/Wavelet/internal/model"
 	"github.com/Rain-kl/Wavelet/internal/task"
-	taskhandlers "github.com/Rain-kl/Wavelet/internal/task/handlers"
 	"github.com/Rain-kl/Wavelet/internal/task/scheduler"
 	"github.com/Rain-kl/Wavelet/pkg/logger"
 	"github.com/gin-gonic/gin"
@@ -21,10 +20,6 @@ import ("fmt"
 
 	"github.com/Rain-kl/Wavelet/internal/common/response")
 
-func init() {
-	taskhandlers.Register()
-}
-
 // ListTaskTypes 获取支持的任务类型列表
 // @Summary 获取支持的任务类型
 // @Description 返回系统支持的所有可调度任务类型列表，包括任务名称、描述、是否支持时间范围等元数据，需要管理员权限

internal/bootstrap/bootstrap.go

@@ -0,0 +1,65 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package bootstrap wires cross-module integrations at the application composition root.
+// All registrations use sync.Once so entry points can call them safely without import-order side effects.
+package bootstrap
+
+import (
+	"sync"
+
+	admin_push "github.com/Rain-kl/Wavelet/internal/apps/admin/push"
+	"github.com/Rain-kl/Wavelet/internal/apps/admin/push/custom_events"
+	taskhandlers "github.com/Rain-kl/Wavelet/internal/task/handlers"
+)
+
+var (
+	registerTasksOnce            sync.Once
+	registerPushDomainEventsOnce sync.Once
+	registerTaskListenersOnce    sync.Once
+)
+
+// RegisterTasks registers all built-in task handlers and metadata.
+func RegisterTasks() {
+	registerTasksOnce.Do(func() {
+		taskhandlers.Register()
+	})
+}
+
+// RegisterPushDomainEvents wires push notification handlers for domain events.
+func RegisterPushDomainEvents() {
+	registerPushDomainEventsOnce.Do(func() {
+		custom_events.Register()
+	})
+}
+
+// RegisterTaskListeners wires operational listeners to task framework hooks.
+func RegisterTaskListeners() {
+	registerTaskListenersOnce.Do(func() {
+		admin_push.RegisterTaskListeners()
+	})
+}
+
+// RegisterAPI wires integrations required by the HTTP API process.
+func RegisterAPI() {
+	RegisterTasks()
+	RegisterPushDomainEvents()
+}
+
+// RegisterWorker wires integrations required by the task worker process.
+func RegisterWorker() {
+	RegisterTasks()
+	RegisterTaskListeners()
+}
+
+// RegisterScheduler wires integrations required by the task scheduler process.
+func RegisterScheduler() {
+	RegisterTasks()
+}
+
+// RegisterAll wires integrations for fused mode (API + Worker + Scheduler).
+func RegisterAll() {
+	RegisterTasks()
+	RegisterPushDomainEvents()
+	RegisterTaskListeners()
+}

internal/cmd/all.go

@@ -9,6 +9,7 @@ import (
 	"log"
 	"sync"
 
+	"github.com/Rain-kl/Wavelet/internal/bootstrap"
 	"github.com/Rain-kl/Wavelet/internal/router"
 	"github.com/Rain-kl/Wavelet/internal/task/scheduler"
 	"github.com/Rain-kl/Wavelet/internal/task/worker"
@@ -20,6 +21,7 @@ var allCmd = &cobra.Command{
 	Short: "以融合模式同时启动 API、Worker 和 Scheduler",
 	Run: func(_ *cobra.Command, _ []string) {
 		log.Println("[All] 融合模式启动")
+		bootstrap.RegisterAll()
 
 		var wg sync.WaitGroup
 

internal/router/router.go

@@ -16,8 +16,8 @@ import (
 	"time"
 
 	admin_push "github.com/Rain-kl/Wavelet/internal/apps/admin/push"
-	"github.com/Rain-kl/Wavelet/internal/apps/admin/push/custom_events"
 	"github.com/Rain-kl/Wavelet/internal/apps/risk_control"
+	"github.com/Rain-kl/Wavelet/internal/bootstrap"
 	router_root "github.com/Rain-kl/Wavelet/internal/router/root"
 	v1 "github.com/Rain-kl/Wavelet/internal/router/v1"
 
@@ -40,8 +40,8 @@ func Serve() {
 	// 初始化 ClickHouse 异步日志写入器
 	risk_control.InitLogWriter()
 
-	// 装配推送模块与领域事件的集成（组合根显式注册，避免 init 副作用）
-	custom_events.Register()
+	// 组合根显式装配跨模块集成（避免 init 副作用与 import 顺序依赖）
+	bootstrap.RegisterAPI()
 
 	// 运行内置事件同步
 	if err := admin_push.SyncEvents(context.Background()); err != nil {

internal/task/executor.go

@@ -26,8 +26,16 @@ import (
 // handlerRegistry 已注册的任务处理器
 var handlerRegistry = make(map[string]TaskHandler)
 
-// OnTaskCompleted is a hook called when a task execution completes.
-var OnTaskCompleted func(ctx context.Context, execution *model.TaskExecution, result *TaskResult, execErr error)
+// CompletedHandler is called when a task execution completes.
+type CompletedHandler func(ctx context.Context, execution *model.TaskExecution, result *TaskResult, execErr error)
+
+var taskCompletedHandlers []CompletedHandler
+
+// OnTaskCompleted registers a handler for task completion events.
+// Handlers must be registered during application bootstrap before processing tasks.
+func OnTaskCompleted(handler CompletedHandler) {
+	taskCompletedHandlers = append(taskCompletedHandlers, handler)
+}
 
 // RegisterHandler 注册任务处理器
 // 传入任务类型标识（对应 constants.go 中的 AsynqTask 常量）和 TaskHandler 实现
@@ -405,9 +413,17 @@ func completeTaskExecution(ctx context.Context, execution *model.TaskExecution,
 		}
 	}
 
-	if OnTaskCompleted != nil {
-		asyncCtx := context.WithoutCancel(ctx)
-		go OnTaskCompleted(asyncCtx, execution, result, execErr)
+	notifyTaskCompleted(ctx, execution, result, execErr)
+}
+
+func notifyTaskCompleted(ctx context.Context, execution *model.TaskExecution, result *TaskResult, execErr error) {
+	if len(taskCompletedHandlers) == 0 {
+		return
+	}
+
+	asyncCtx := context.WithoutCancel(ctx)
+	for _, handler := range taskCompletedHandlers {
+		go handler(asyncCtx, execution, result, execErr)
 	}
 }
 

internal/task/scheduler/scheduler.go

@@ -11,6 +11,7 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/Rain-kl/Wavelet/internal/bootstrap"
 	"github.com/Rain-kl/Wavelet/internal/model"
 	"github.com/Rain-kl/Wavelet/internal/task"
 	"github.com/Rain-kl/Wavelet/pkg/logger"
@@ -32,6 +33,8 @@ func GetAsynqClient() *asynq.Client {
 
 // StartScheduler 启动调度器 (该函数阻塞，直到调度器退出)
 func StartScheduler() error {
+	bootstrap.RegisterScheduler()
+
 	var err error
 	schedulerOnce.Do(func() {
 		quitChan = make(chan struct{})

internal/task/worker/worker.go

@@ -7,22 +7,18 @@ package worker
 import (
 	"time"
 
+	"github.com/Rain-kl/Wavelet/internal/bootstrap"
 	"github.com/Rain-kl/Wavelet/internal/config"
 	"github.com/Rain-kl/Wavelet/internal/task"
-	taskhandlers "github.com/Rain-kl/Wavelet/internal/task/handlers"
 	"github.com/hibiken/asynq"
 )
 
 // workerShutdownTimeout Worker 优雅关闭超时时间
 const workerShutdownTimeout = 3 * time.Minute
 
-func init() {
-	// 注册所有任务处理器
-	taskhandlers.Register()
-}
-
 // StartWorker 启动任务处理服务器
 func StartWorker() error {
+	bootstrap.RegisterWorker()
 	asynqServer := asynq.NewServer(
 		task.RedisOpt,
 		asynq.Config{