diff --git a/internal/pkg/config/config.go b/internal/pkg/config/config.go
index cbfff40e..082de4dc 100644
--- a/internal/pkg/config/config.go
+++ b/internal/pkg/config/config.go
@@ -315,27 +315,30 @@ func bindConfigDefaults(v *viper.Viper) {
 }
 
 func bindEnvironmentAliases(v *viper.Viper) {
-	_ = v.BindEnv("server.port", "PORT", "SERVER_PORT", "AGENT_DESK_SERVER_PORT")
-	_ = v.BindEnv("server.companyName", "COMPANY_NAME", "NEXT_PUBLIC_COMPANY_NAME", "BRAND_NAME", "BRAND_COMPANY_NAME", "AGENT_DESK_SERVER_COMPANYNAME")
-	_ = v.BindEnv("server.companyLogoUrl", "COMPANY_LOGO_URL", "NEXT_PUBLIC_COMPANY_LOGO_URL", "BRAND_LOGO_URL", "AGENT_DESK_SERVER_COMPANYLOGOURL")
-	_ = v.BindEnv("db.type", "DATABASE_TYPE", "DB_TYPE", "AGENT_DESK_DB_TYPE")
-	_ = v.BindEnv("db.dsn", "DATABASE_URL", "DB_DSN", "AGENT_DESK_DB_DSN")
-	_ = v.BindEnv("auth.passwordLoginEnabled", "PASSWORD_LOGIN_ENABLED", "AGENT_DESK_AUTH_PASSWORDLOGINENABLED")
-	_ = v.BindEnv("auth.tokenTTLHours", "AUTH_TOKEN_TTL_HOURS", "AGENT_DESK_AUTH_TOKENTTLHOURS")
-	_ = v.BindEnv("customerSession.secret", "CUSTOMER_SESSION_SECRET", "SESSION_SECRET", "JWT_SECRET", "AGENT_DESK_CUSTOMERSESSION_SECRET")
-	_ = v.BindEnv("storage.default", "STORAGE_DEFAULT", "STORAGE_TYPE", "AGENT_DESK_STORAGE_DEFAULT")
-	_ = v.BindEnv("storage.local.root", "STORAGE_LOCAL_ROOT", "AGENT_DESK_STORAGE_LOCAL_ROOT")
-	_ = v.BindEnv("storage.local.baseUrl", "STORAGE_LOCAL_BASE_URL", "AGENT_DESK_STORAGE_LOCAL_BASEURL")
-	_ = v.BindEnv("vectorDB.type", "VECTOR_DB_TYPE", "AGENT_DESK_VECTORDB_TYPE")
-	_ = v.BindEnv("vectorDB.qdrant.host", "QDRANT_HOST", "AGENT_DESK_VECTORDB_QDRANT_HOST")
-	_ = v.BindEnv("vectorDB.qdrant.grpcPort", "QDRANT_GRPC_PORT", "QDRANT_PORT", "AGENT_DESK_VECTORDB_QDRANT_GRPCPORT")
-	_ = v.BindEnv("vectorDB.qdrant.apiKey", "QDRANT_API_KEY", "AGENT_DESK_VECTORDB_QDRANT_APIKEY")
-	_ = v.BindEnv("oidc.enabled", "OIDC_ENABLED", "AGENT_DESK_OIDC_ENABLED")
-	_ = v.BindEnv("oidc.issuer", "OIDC_ISSUER", "AGENT_DESK_OIDC_ISSUER")
-	_ = v.BindEnv("oidc.clientId", "OIDC_CLIENT_ID", "CUSTOM_OAUTH_CLIENT_ID", "AGENT_DESK_OIDC_CLIENTID")
-	_ = v.BindEnv("oidc.clientSecret", "OIDC_CLIENT_SECRET", "CUSTOM_OAUTH_CLIENT_SECRET", "AGENT_DESK_OIDC_CLIENTSECRET")
-	_ = v.BindEnv("oidc.redirectUrl", "OIDC_REDIRECT_URL", "CUSTOM_OAUTH_REDIRECT_URI", "AGENT_DESK_OIDC_REDIRECTURL")
-	_ = v.BindEnv("webhook.orgSyncSecret", "ORG_SYNC_SECRET", "WEBHOOK_SECRET", "AGENT_DESK_WEBHOOK_ORGSYNCSECRET")
+	// Prefixed AGENT_DESK_* aliases are listed first so that ambient legacy
+	// variables (PORT, DATABASE_URL, ...) cannot silently override the
+	// documented configuration.
+	_ = v.BindEnv("server.port", "AGENT_DESK_SERVER_PORT", "PORT", "SERVER_PORT")
+	_ = v.BindEnv("server.companyName", "AGENT_DESK_SERVER_COMPANYNAME", "COMPANY_NAME", "NEXT_PUBLIC_COMPANY_NAME", "BRAND_NAME", "BRAND_COMPANY_NAME")
+	_ = v.BindEnv("server.companyLogoUrl", "AGENT_DESK_SERVER_COMPANYLOGOURL", "COMPANY_LOGO_URL", "NEXT_PUBLIC_COMPANY_LOGO_URL", "BRAND_LOGO_URL")
+	_ = v.BindEnv("db.type", "AGENT_DESK_DB_TYPE", "DATABASE_TYPE", "DB_TYPE")
+	_ = v.BindEnv("db.dsn", "AGENT_DESK_DB_DSN", "DATABASE_URL", "DB_DSN")
+	_ = v.BindEnv("auth.passwordLoginEnabled", "AGENT_DESK_AUTH_PASSWORDLOGINENABLED", "PASSWORD_LOGIN_ENABLED")
+	_ = v.BindEnv("auth.tokenTTLHours", "AGENT_DESK_AUTH_TOKENTTLHOURS", "AUTH_TOKEN_TTL_HOURS")
+	_ = v.BindEnv("customerSession.secret", "AGENT_DESK_CUSTOMERSESSION_SECRET", "CUSTOMER_SESSION_SECRET", "SESSION_SECRET", "JWT_SECRET")
+	_ = v.BindEnv("storage.default", "AGENT_DESK_STORAGE_DEFAULT", "STORAGE_DEFAULT", "STORAGE_TYPE")
+	_ = v.BindEnv("storage.local.root", "AGENT_DESK_STORAGE_LOCAL_ROOT", "STORAGE_LOCAL_ROOT")
+	_ = v.BindEnv("storage.local.baseUrl", "AGENT_DESK_STORAGE_LOCAL_BASEURL", "STORAGE_LOCAL_BASE_URL")
+	_ = v.BindEnv("vectorDB.type", "AGENT_DESK_VECTORDB_TYPE", "VECTOR_DB_TYPE")
+	_ = v.BindEnv("vectorDB.qdrant.host", "AGENT_DESK_VECTORDB_QDRANT_HOST", "QDRANT_HOST")
+	_ = v.BindEnv("vectorDB.qdrant.grpcPort", "AGENT_DESK_VECTORDB_QDRANT_GRPCPORT", "QDRANT_GRPC_PORT", "QDRANT_PORT")
+	_ = v.BindEnv("vectorDB.qdrant.apiKey", "AGENT_DESK_VECTORDB_QDRANT_APIKEY", "QDRANT_API_KEY")
+	_ = v.BindEnv("oidc.enabled", "AGENT_DESK_OIDC_ENABLED", "OIDC_ENABLED")
+	_ = v.BindEnv("oidc.issuer", "AGENT_DESK_OIDC_ISSUER", "OIDC_ISSUER")
+	_ = v.BindEnv("oidc.clientId", "AGENT_DESK_OIDC_CLIENTID", "OIDC_CLIENT_ID", "CUSTOM_OAUTH_CLIENT_ID")
+	_ = v.BindEnv("oidc.clientSecret", "AGENT_DESK_OIDC_CLIENTSECRET", "OIDC_CLIENT_SECRET", "CUSTOM_OAUTH_CLIENT_SECRET")
+	_ = v.BindEnv("oidc.redirectUrl", "AGENT_DESK_OIDC_REDIRECTURL", "OIDC_REDIRECT_URL", "CUSTOM_OAUTH_REDIRECT_URI")
+	_ = v.BindEnv("webhook.orgSyncSecret", "AGENT_DESK_WEBHOOK_ORGSYNCSECRET", "ORG_SYNC_SECRET", "WEBHOOK_SECRET")
 }
 
 func normalizeLoadedConfig(cfg *Config) {
diff --git a/internal/services/channel_message_outbox_service.go b/internal/services/channel_message_outbox_service.go
index 2660a8bc..12014241 100644
--- a/internal/services/channel_message_outbox_service.go
+++ b/internal/services/channel_message_outbox_service.go
@@ -254,12 +254,18 @@ func (s *channelMessageOutboxService) ListPending(channelType string, limit int)
 	if limit <= 0 {
 		limit = 20
 	}
+	now := time.Now()
 	cnd := sqls.NewCnd().
 		Eq("channel_type", strings.TrimSpace(channelType)).
 		In("send_status", []string{
 			string(enums.ChannelMessageOutboxStatusPending),
 			string(enums.ChannelMessageOutboxStatusFailed),
 		}).
+		// Only rows whose backoff has elapsed are eligible; ordering by
+		// next_retry_at keeps a backlog of not-yet-due retries from starving
+		// newer pending sends.
+		Lte("next_retry_at", now).
+		Asc("next_retry_at").
 		Asc("id").
 		Limit(limit)
 	return s.Find(cnd)
diff --git a/internal/services/role_service.go b/internal/services/role_service.go
index cf1046b8..6003f447 100644
--- a/internal/services/role_service.go
+++ b/internal/services/role_service.go
@@ -2,6 +2,7 @@ package services
 
 import (
 	"agent-desk/internal/models"
+	"agent-desk/internal/pkg/constants"
 	"agent-desk/internal/pkg/dto"
 	"agent-desk/internal/pkg/dto/request"
 	"agent-desk/internal/pkg/enums"
@@ -172,6 +173,9 @@ func (s *roleService) AssignPermissions(roleID int64, permissionIDs []int64, ope
 	if role == nil {
 		return errorsx.InvalidParamI18n("error.e0305")
 	}
+	if role.IsSystem && (operator == nil || !slices.Contains(operator.Roles, string(constants.RoleCodeSuperAdmin))) {
+		return errorsx.ForbiddenI18n("error.e0293")
+	}
 
 	return s.replaceRolePermissions(roleID, permissionIDs, operator)
 }
diff --git a/internal/services/user_service.go b/internal/services/user_service.go
index c0c2f25d..67610673 100644
--- a/internal/services/user_service.go
+++ b/internal/services/user_service.go
@@ -2,6 +2,7 @@ package services
 
 import (
 	"agent-desk/internal/models"
+	"agent-desk/internal/pkg/constants"
 	"agent-desk/internal/pkg/dto"
 	"agent-desk/internal/pkg/dto/request"
 	"agent-desk/internal/pkg/enums"
@@ -262,6 +263,9 @@ func (s *userService) replaceUserRolesDB(db *gorm.DB, userID int64, roleIDs []in
 		if role.Status != enums.StatusOk {
 			return errorsx.InvalidParamI18n("error.e0291")
 		}
+		if role.IsSystem && (operator == nil || !slices.Contains(operator.Roles, string(constants.RoleCodeSuperAdmin))) {
+			return errorsx.ForbiddenI18n("error.e0293")
+		}
 		relation := &models.UserRole{
 			UserID:      userID,
 			RoleID:      roleID,
@@ -279,6 +283,18 @@ func (s *userService) changePassword(userID int64, password string, operator *dt
 	if user == nil || user.DeletedAt != nil {
 		return errorsx.InvalidParamI18n("error.e0255")
 	}
+	if operator != nil && operator.UserID != userID && !slices.Contains(operator.Roles, string(constants.RoleCodeSuperAdmin)) {
+		var superAdminCount int64
+		if err := sqls.DB().Model(&models.UserRole{}).
+			Joins("JOIN t_role ON t_role.id = t_user_role.role_id").
+			Where("t_user_role.user_id = ? AND t_role.code = ?", userID, string(constants.RoleCodeSuperAdmin)).
+			Count(&superAdminCount).Error; err != nil {
+			return err
+		}
+		if superAdminCount > 0 {
+			return errorsx.ForbiddenI18n("error.e0293")
+		}
+	}
 	if strings.TrimSpace(password) == "" {
 		return errorsx.InvalidParamI18n("error.e0220")
 	}
diff --git a/internal/services/ws_service.go b/internal/services/ws_service.go
index 2f37acc2..53c07a8b 100644
--- a/internal/services/ws_service.go
+++ b/internal/services/ws_service.go
@@ -2,6 +2,7 @@ package services
 
 import (
 	"agent-desk/internal/models"
+	"agent-desk/internal/pkg/constants"
 	"agent-desk/internal/pkg/dto"
 	"agent-desk/internal/pkg/dto/response"
 	"agent-desk/internal/pkg/enums"
@@ -13,6 +14,7 @@ import (
 	"fmt"
 	"log/slog"
 	"net/http"
+	"slices"
 	"strconv"
 	"strings"
 	"sync/atomic"
@@ -626,7 +628,13 @@ func (s *wsService) canSubscribeConversation(session *ClientSession, conversatio
 		return false
 	}
 	if session.Role == realtimeRoleAdmin {
-		return true
+		// Staff sessions must hold the same conversation-view permission the
+		// REST endpoints require; a bare admin-role websocket must not become
+		// a side channel around RequirePermission.
+		if session.Principal != nil && slices.Contains(session.Principal.Permissions, constants.PermissionConversationView.Code) {
+			return true
+		}
+		return false
 	}
 	conversation := ConversationService.Get(conversationID)
 	if conversation == nil {