perf(storage): 极简化任务历史并增加保留治理

停止持久化 provider 原始响应、兼容响应快照、attempt/event/outbox 重复 JSON，并由标准任务结果动态生成 Kling/Keling/Volces 兼容响应。

增加事件去重与预算、极简 callback 投递、7/30 天分批清理、安全删除条件、并发迁移索引及可实际恢复的任务域排除备份。历史清理默认关闭，待兼容协议和异步恢复在线验证后单独启用。

验证：Go 全量测试与 go vet、PostgreSQL 18 集成与实际备份恢复、迁移安全测试、bash -n、ShellCheck、Compose 配置和人工发布脚本测试均通过。

apps/api/internal/securityevents/metrics.go

@@ -55,6 +55,9 @@ type Metrics struct {
 	leaseRenewalSuccess        atomic.Uint64
 	leaseRenewalFailure        atomic.Uint64
 	leaseRenewalLost           atomic.Uint64
+	taskEventDuplicate         atomic.Uint64
+	taskEventUnknownType       atomic.Uint64
+	taskEventBudgetExceeded    atomic.Uint64
 }
 
 var processingDurationBounds = [...]time.Duration{
@@ -169,6 +172,17 @@ func (m *Metrics) ObserveConcurrencyLeaseRenewal(outcome string) {
 	}
 }
 
+func (m *Metrics) ObserveTaskEventSkip(reason string) {
+	switch reason {
+	case "duplicate":
+		m.taskEventDuplicate.Add(1)
+	case "budget_exceeded":
+		m.taskEventBudgetExceeded.Add(1)
+	default:
+		m.taskEventUnknownType.Add(1)
+	}
+}
+
 func (m *Metrics) Handler(provider MetricsSnapshotProvider, issuer, audience string, enabled bool) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		mode := "disabled"
@@ -273,6 +287,11 @@ func (m *Metrics) Handler(provider MetricsSnapshotProvider, issuer, audience str
 			{"failure", m.leaseRenewalFailure.Load()},
 			{"lost", m.leaseRenewalLost.Load()},
 		})
+		outcomeCounters(w, "easyai_gateway_task_events_skipped_total", "Task events skipped before persistence by bounded reason.", []outcomeValue{
+			{"duplicate", m.taskEventDuplicate.Load()},
+			{"unknown_type", m.taskEventUnknownType.Load()},
+			{"budget_exceeded", m.taskEventBudgetExceeded.Load()},
+		})
 	})
 }