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/httpapi/volces_compat_handlers_test.go

@@ -7,23 +7,22 @@ import (
 	"github.com/easyai/easyai-ai-gateway/apps/api/internal/store"
 )
 
-func TestVolcesCompatibleTaskPreservesNativeOfficialFieldsWithoutGatewayExtensions(t *testing.T) {
+func TestVolcesCompatibleTaskBuildsProtocolResponseFromCanonicalResult(t *testing.T) {
 	now := time.Date(2026, 7, 18, 8, 0, 0, 0, time.UTC)
 	task := store.GatewayTask{
 		ID: "gateway-task-1", Kind: "videos.generations", Status: "succeeded", Model: "doubao-seedance-2-0-mini-260615",
 		RemoteTaskID: "cgt-upstream-1", CreatedAt: now, UpdatedAt: now.Add(time.Second),
 		Result: map[string]any{
-			"raw": map[string]any{
-				"id": "cgt-upstream-1", "model": "doubao-seedance-2-0-mini-260615", "status": "succeeded",
-				"content": map[string]any{"video_url": "https://example.com/out.mp4"}, "usage": map[string]any{"total_tokens": 9},
-				"future_official_field": "preserved",
-			},
+			"id": "cgt-upstream-1", "model": "doubao-seedance-2-0-mini-260615", "status": "succeeded",
+			"data":                  []any{map[string]any{"url": "https://example.com/out.mp4", "type": "video"}},
+			"future_official_field": "not-whitelisted",
 		},
+		Usage:    map[string]any{"totalTokens": 9},
 		Billings: []any{map[string]any{"amount": 3}}, BillingSummary: map[string]any{"currency": "resource"}, FinalChargeAmount: 3,
 		Attempts: []store.TaskAttempt{{Provider: "volces"}},
 	}
 	got := volcesCompatibleTask(task)
-	if got["id"] != task.RemoteTaskID || got["status"] != "succeeded" || got["future_official_field"] != "preserved" {
+	if got["id"] != task.RemoteTaskID || got["status"] != "succeeded" || got["future_official_field"] != nil {
 		t.Fatalf("unexpected compatibility identity/status: %+v", got)
 	}
 	content, _ := got["content"].(map[string]any)