feat(sub): refine Happ routing presets, serverDescription escaping, and auto-detect placement (#6488)

* feat(sub): refine Happ routing presets, serverDescription escaping, and auto-detect placement

* fix(sub): address PR review findings on routing parity, agent regex, and i18n

internal/sub/endpoint.go

@@ -1,6 +1,7 @@
 package sub
 
 import (
+	"encoding/base64"
 	"strings"
 
 	"github.com/mhsanaei/3x-ui/v3/internal/database/model"
@@ -20,10 +21,11 @@ import (
 // because three behaviors branch on the raw string (keep-base, obj["tls"]
 // rewrite, none-strip).
 type ShareEndpoint struct {
-	Address  string
-	Port     int
-	Remark   string // extra remark slot fed to genRemark, not a rendered remark
-	ForceTls string
+	Address           string
+	Port              int
+	Remark            string // extra remark slot fed to genRemark, not a rendered remark
+	ServerDescription string // subtitle caption displayed in Happ client
+	ForceTls          string
 
 	// ep is the source externalProxy entry. nil for host/default endpoints.
 	ep map[string]any
@@ -38,6 +40,7 @@ func externalProxyToEndpoint(ep map[string]any) ShareEndpoint {
 		e.Port = int(p)
 	}
 	e.Remark, _ = ep["remark"].(string)
+	e.ServerDescription, _ = ep["serverDescription"].(string)
 	e.ForceTls, _ = ep["forceTls"].(string)
 	return e
 }
@@ -106,10 +109,14 @@ func (s *SubService) buildEndpointLinks(
 		applyEndpointHostPath(e, nextParams)
 		applyEndpointFinalMask(e, nextParams)
 		applyEndpointAllowInsecure(e, nextParams, securityToApply)
+		remark := makeRemark(e)
+		if e.ServerDescription != "" {
+			remark = appendHappServerDescription(remark, e.ServerDescription)
+		}
 		links = append(links, buildLinkWithParamsAndSecurity(
 			makeLink(e),
 			nextParams,
-			makeRemark(e),
+			remark,
 			securityToApply,
 			e.ForceTls == "none",
 		))
@@ -117,6 +124,14 @@ func (s *SubService) buildEndpointLinks(
 	return strings.Join(links, "\n")
 }
 
+func appendHappServerDescription(remark, desc string) string {
+	if desc == "" {
+		return remark
+	}
+	encoded := base64.StdEncoding.EncodeToString([]byte(desc))
+	return remark + "?serverDescription=" + encoded
+}
+
 // buildEndpointVmessLinks renders one VMess base64-JSON link per endpoint.
 func (s *SubService) buildEndpointVmessLinks(eps []ShareEndpoint, baseObj map[string]any, inbound *model.Inbound, email string, transport string) string {
 	var links strings.Builder
@@ -132,6 +147,9 @@ func (s *SubService) buildEndpointVmessLinks(eps []ShareEndpoint, baseObj map[st
 		if e.ForceTls != "same" {
 			newObj["tls"] = e.ForceTls
 		}
+		if e.ServerDescription != "" {
+			newObj["serverDescription"] = e.ServerDescription
+		}
 		applyEndpointTLSObj(e, newObj, securityToApply)
 		applyEndpointHostPathObj(e, newObj)
 		applyEndpointFinalMaskObj(e, newObj)