feat(sub): per-inbound sort order for subscription links

Add a subSortIndex field to inbounds that controls the order of links
in subscription output only: the raw sub body, the HTML sub page, and
the JSON/Clash formats (all served from the same query). Lower values
come first; ties keep id order. The panel inbound list is unaffected.

The value is editable in the inbound form next to the share-address
fields, propagates to nodes via wireInbound, and follows the usual
node-sync rules (copied on import, mirrored while not dirty, never a
structural change).

Rescoped from #5214 by @Ponywka.

internal/sub/service.go

@@ -284,7 +284,7 @@ func (s *SubService) getInboundsBySubId(subId string) ([]*model.Inbound, error)
 		WHERE
 			inbounds.protocol in ('vmess','vless','trojan','shadowsocks','hysteria')
 			AND clients.sub_id = ? AND inbounds.enable = ?
-	)`, subId, true).Find(&inbounds).Error
+	)`, subId, true).Order("sub_sort_index ASC").Order("id ASC").Find(&inbounds).Error
 	if err != nil {
 		return nil, err
 	}

internal/sub/service_sort_test.go

@@ -0,0 +1,79 @@
+package sub
+
+import (
+	"fmt"
+	"path/filepath"
+	"testing"
+
+	"github.com/mhsanaei/3x-ui/v3/internal/database"
+	"github.com/mhsanaei/3x-ui/v3/internal/database/model"
+)
+
+// TestGetSubs_OrdersBySubSortIndexThenId verifies that subscription output
+// lists inbound links ordered by sub_sort_index ASC, breaking ties by id ASC.
+// The same query feeds the raw body, the HTML sub page, and the JSON/Clash
+// formats, so asserting on GetSubs covers all of them.
+func TestGetSubs_OrdersBySubSortIndexThenId(t *testing.T) {
+	dbDir := t.TempDir()
+	t.Setenv("XUI_DB_FOLDER", dbDir)
+	if err := database.InitDB(filepath.Join(dbDir, "x-ui.db")); err != nil {
+		t.Fatalf("InitDB: %v", err)
+	}
+	t.Cleanup(func() { _ = database.CloseDB() })
+
+	const subId = "sub-sort"
+	db := database.GetDB()
+
+	seed := []struct {
+		tag          string
+		port         int
+		subSortIndex int
+		email        string
+		uuid         string
+	}{
+		// Created in this order on purpose: without the ORDER BY the links
+		// would come out s3, s1, s2a, s2b (creation order).
+		{"sort-3", 42101, 3, "s3@example.com", "0d68a695-4be1-4d92-a9c3-8c0f1c2cf001"},
+		{"sort-1", 42102, 1, "s1@example.com", "0d68a695-4be1-4d92-a9c3-8c0f1c2cf002"},
+		{"sort-2a", 42103, 2, "s2a@example.com", "0d68a695-4be1-4d92-a9c3-8c0f1c2cf003"},
+		{"sort-2b", 42104, 2, "s2b@example.com", "0d68a695-4be1-4d92-a9c3-8c0f1c2cf004"},
+	}
+	for _, s := range seed {
+		settings := fmt.Sprintf(`{"clients": [{"id": %q, "email": %q, "subId": %q, "enable": true}]}`, s.uuid, s.email, subId)
+		ib := &model.Inbound{
+			UserId:         1,
+			Tag:            s.tag,
+			Enable:         true,
+			Port:           s.port,
+			Protocol:       model.VLESS,
+			Settings:       settings,
+			StreamSettings: `{"network": "tcp", "security": "none"}`,
+			SubSortIndex:   s.subSortIndex,
+		}
+		if err := db.Create(ib).Error; err != nil {
+			t.Fatalf("seed inbound %s: %v", s.tag, err)
+		}
+		client := &model.ClientRecord{Email: s.email, SubID: subId, UUID: s.uuid, Enable: true}
+		if err := db.Create(client).Error; err != nil {
+			t.Fatalf("seed client %s: %v", s.email, err)
+		}
+		if err := db.Create(&model.ClientInbound{ClientId: client.Id, InboundId: ib.Id}).Error; err != nil {
+			t.Fatalf("seed client_inbound %s: %v", s.email, err)
+		}
+	}
+
+	s := NewSubService(false, "-ieo")
+	links, emails, _, _, err := s.GetSubs(subId, "sub.example.com")
+	if err != nil {
+		t.Fatalf("GetSubs: %v", err)
+	}
+	if len(links) != len(seed) {
+		t.Fatalf("links = %d, want %d", len(links), len(seed))
+	}
+	want := []string{"s1@example.com", "s2a@example.com", "s2b@example.com", "s3@example.com"}
+	for i, email := range want {
+		if emails[i] != email {
+			t.Fatalf("emails order = %v, want %v (sub_sort_index ASC, id ASC)", emails, want)
+		}
+	}
+}