feat(acceptance): 增加生产同构媒体压力验收模式

引入动态流量门禁、隔离验收身份与协议级 Gemini/Volces 模拟器，覆盖双站点 API、Worker、PostgreSQL、River、账务、回调和媒体物化链路。

新增 P24/P28/P32 容量阶梯、Worker 强杀恢复、真实小流量 canary、CAS 放量和失败保持 validation 的生产编排；Worker 执行槽、连接池、媒体并发和双站点副本数改为环境配置。

验证：Go 全量测试、真实 PostgreSQL 迁移集成测试、迁移安全检查、OpenAPI 生成、ShellCheck、Kustomize、gofmt 和 git diff --check。

apps/api/internal/store/postgres.go

@@ -545,6 +545,7 @@ type CreateTaskInput struct {
 	Model                  string                `json:"model"`
 	ExternalTaskID         string                `json:"externalTaskId,omitempty"`
 	RunMode                string                `json:"runMode"`
+	AcceptanceRunID        string                `json:"acceptanceRunId,omitempty"`
 	Async                  bool                  `json:"async"`
 	Request                map[string]any        `json:"request"`
 	ConversationID         string                `json:"conversationId"`
@@ -564,6 +565,7 @@ type GatewayTask struct {
 	ExternalTaskID                string         `json:"externalTaskId,omitempty"`
 	Kind                          string         `json:"kind"`
 	RunMode                       string         `json:"runMode"`
+	AcceptanceRunID               string         `json:"acceptanceRunId,omitempty"`
 	UserID                        string         `json:"userId"`
 	GatewayUserID                 string         `json:"gatewayUserId,omitempty"`
 	UserSource                    string         `json:"userSource,omitempty"`
@@ -629,7 +631,8 @@ type GatewayTask struct {
 }
 
 const gatewayTaskColumns = `
-id::text, COALESCE(external_task_id, ''), kind, run_mode, user_id, COALESCE(gateway_user_id::text, ''), user_source,
+id::text, COALESCE(external_task_id, ''), kind, run_mode, COALESCE(acceptance_run_id::text, ''),
+user_id, COALESCE(gateway_user_id::text, ''), user_source,
 COALESCE(gateway_tenant_id::text, ''), COALESCE(tenant_id, ''), COALESCE(tenant_key, ''),
 COALESCE(api_key_id, ''), COALESCE(api_key_name, ''), COALESCE(api_key_prefix, ''),
 COALESCE(user_group_id::text, ''), COALESCE(user_group_key, ''), model,
@@ -2103,15 +2106,19 @@ func (s *Store) CreateTaskIdempotent(ctx context.Context, input CreateTaskInput,
 
 	task, err := scanGatewayTask(tx.QueryRow(ctx, `
 	INSERT INTO gateway_tasks (
-	  external_task_id, kind, run_mode, user_id, gateway_user_id, user_source, gateway_tenant_id, tenant_id, tenant_key,
+	  external_task_id, kind, run_mode, acceptance_run_id, user_id, gateway_user_id, user_source, gateway_tenant_id, tenant_id, tenant_key,
 	  api_key_id, api_key_name, api_key_prefix, user_group_id, user_group_key,
 	  model, requested_model, request, async_mode, status, result, billings, conversation_id, new_message_count,
 	  idempotency_key_hash, idempotency_request_hash, finished_at
 	)
-	VALUES (NULLIF($1, ''), $2, $3, $4, NULLIF($5, '')::uuid, COALESCE(NULLIF($6, ''), 'gateway'), NULLIF($7, '')::uuid, NULLIF($8, ''), NULLIF($9, ''), NULLIF($10, ''), NULLIF($11, ''), NULLIF($12, ''), NULLIF($13, '')::uuid, NULLIF($14, ''), $15, $15, $16, $17, $18, $19::jsonb, $20::jsonb, NULLIF($21, '')::uuid, $22, NULLIF($23, ''), NULLIF($24, ''), NULL)
+	VALUES (NULLIF($1, ''), $2, $3, NULLIF($4, '')::uuid, $5, NULLIF($6, '')::uuid, COALESCE(NULLIF($7, ''), 'gateway'), NULLIF($8, '')::uuid, NULLIF($9, ''), NULLIF($10, ''), NULLIF($11, ''), NULLIF($12, ''), NULLIF($13, ''), NULLIF($14, '')::uuid, NULLIF($15, ''), $16, $16, $17, $18, $19, $20::jsonb, $21::jsonb, NULLIF($22, '')::uuid, $23, NULLIF($24, ''), NULLIF($25, ''), NULL)
 	ON CONFLICT (user_id, idempotency_key_hash) WHERE idempotency_key_hash IS NOT NULL DO NOTHING
 	RETURNING `+gatewayTaskColumns,
-		strings.TrimSpace(input.ExternalTaskID), input.Kind, runMode, user.ID, user.GatewayUserID, user.Source, user.GatewayTenantID, user.TenantID, user.TenantKey, user.APIKeyID, user.APIKeyName, user.APIKeyPrefix, user.UserGroupID, user.UserGroupKey, input.Model, requestBody, input.Async, status, resultBody, billingsBody, input.ConversationID, input.NewMessageCount, strings.TrimSpace(input.IdempotencyKeyHash), strings.TrimSpace(input.IdempotencyRequestHash),
+		strings.TrimSpace(input.ExternalTaskID), input.Kind, runMode, strings.TrimSpace(input.AcceptanceRunID),
+		user.ID, user.GatewayUserID, user.Source, user.GatewayTenantID, user.TenantID, user.TenantKey,
+		user.APIKeyID, user.APIKeyName, user.APIKeyPrefix, user.UserGroupID, user.UserGroupKey,
+		input.Model, requestBody, input.Async, status, resultBody, billingsBody, input.ConversationID,
+		input.NewMessageCount, strings.TrimSpace(input.IdempotencyKeyHash), strings.TrimSpace(input.IdempotencyRequestHash),
 	))
 	replayed := false
 	if errors.Is(err, pgx.ErrNoRows) && strings.TrimSpace(input.IdempotencyKeyHash) != "" {
@@ -2204,6 +2211,7 @@ func scanGatewayTask(scanner taskScanner) (GatewayTask, error) {
 		&task.ExternalTaskID,
 		&task.Kind,
 		&task.RunMode,
+		&task.AcceptanceRunID,
 		&task.UserID,
 		&task.GatewayUserID,
 		&task.UserSource,
@@ -2461,6 +2469,12 @@ func normalizeRunMode(input string, request map[string]any) string {
 	if mode == "simulation" {
 		return "simulation"
 	}
+	if mode == "acceptance" {
+		return "acceptance"
+	}
+	if mode == "acceptance_canary" {
+		return "acceptance_canary"
+	}
 	return "production"
 }