fix(server): prevent refinement crashes from missing private option messages

go/internal/server/player/equipment.go

@@ -351,9 +351,14 @@ func EquipmentWire(entry Equipment) []byte {
 	for _, option := range entry.SubOption {
 		base = wire.AppendBytes(base, 4, equipmentOptionWire(option))
 	}
+	// The native ResolvedPrivateOption getter dereferences PrivateOption before
+	// checking IsValid. A present empty message selects its GameData fallback;
+	// an omitted field leaves the protobuf object null and crashes the UI.
+	var private []byte
 	if entry.PrivateOption != nil {
-		base = wire.AppendBytes(base, 5, equipmentOptionWire(*entry.PrivateOption))
+		private = equipmentOptionWire(*entry.PrivateOption)
 	}
+	base = wire.AppendBytes(base, 5, private)
 	for _, rank := range entry.Rank {
 		base = wire.AppendVarint(base, 6, rank)
 	}

go/internal/server/player/equipment_test.go

@@ -45,6 +45,7 @@ func TestEquipmentUpgradeAndSequenceUseGameDataCosts(t *testing.T) {
 	if err != nil || !handled || code != 37 {
 		t.Fatalf("single upgrade code=%d handled=%v err=%v", code, handled, err)
 	}
+	assertEquipmentPrivateMessage(t, response)
 	encoded, found, err := wire.Bytes(response, 1)
 	if err != nil || !found {
 		t.Fatalf("single upgrade equipment: %v", err)
@@ -60,6 +61,7 @@ func TestEquipmentUpgradeAndSequenceUseGameDataCosts(t *testing.T) {
 	if err != nil || !handled || code != 176 {
 		t.Fatalf("sequence upgrade code=%d handled=%v err=%v", code, handled, err)
 	}
+	assertEquipmentPrivateMessage(t, response)
 	if result, _, _ := wire.Varint(response, 3); result != equipUpgradeStopMaxLevel {
 		t.Fatalf("sequence result=%d", result)
 	}
@@ -125,6 +127,7 @@ func TestEquipmentSmeltingImprovesByTotalScoreAndReplaysWithoutSecondCharge(t *t
 	if err != nil || !handled || code != 105 {
 		t.Fatalf("smelting code=%d handled=%v err=%v", code, handled, err)
 	}
+	assertEquipmentPrivateMessage(t, response)
 	if result, found, _ := wire.Varint(response, 3); found || result != 0 {
 		t.Fatalf("successful smelting result=%d found=%v", result, found)
 	}
@@ -227,6 +230,7 @@ func TestEquipmentSequenceSmeltingRepeatsAndStopsAtTargetScore(t *testing.T) {
 	if err != nil || !handled || code != 177 {
 		t.Fatalf("sequence smelting code=%d handled=%v err=%v", code, handled, err)
 	}
+	assertEquipmentPrivateMessage(t, response)
 	if result, _, _ := wire.Varint(response, 3); result != equipUpgradeStopTargetLevel {
 		t.Fatalf("sequence smelting result=%d", result)
 	}
@@ -723,3 +727,45 @@ func TestEquipmentChangeReplacesOnlyMatchingGameDataSlot(t *testing.T) {
 		t.Fatalf("changed equipment=%+v", got)
 	}
 }
+
+func assertEquipmentPrivateMessage(t *testing.T, response []byte) {
+	t.Helper()
+	entry, ok, err := wire.Bytes(response, 1)
+	if err != nil || !ok {
+		t.Fatal("equipment entry absent", err)
+	}
+	base, ok, err := wire.Bytes(entry, 5)
+	if err != nil || !ok {
+		t.Fatal("equipment base absent", err)
+	}
+	private, ok, err := wire.Bytes(base, 5)
+	if err != nil || !ok {
+		t.Fatal("native PrivateOption reference would be null", err)
+	}
+	if len(private) != 0 {
+		t.Fatal("ordinary equipment has unexpected private option")
+	}
+}
+
+func TestEquipmentWirePrivateObjectPresenceAndExplicitOption(t *testing.T) {
+	for _, private := range []*EquipmentOption{nil, {GroupID: 301, ID: 2}} {
+		entry := Equipment{ID: 943035, InvenIndex: 1, Rank: []uint64{1, 2, 3}, PrivateOption: private}
+		base, _, _ := wire.Bytes(EquipmentWire(entry), 5)
+		option, present, err := wire.Bytes(base, 5)
+		if err != nil || !present {
+			t.Fatal("PrivateOption was omitted", err)
+		}
+		group, _, _ := wire.Varint(option, 1)
+		id, _, _ := wire.Varint(option, 2)
+		if private == nil {
+			if len(option) != 0 || group != 0 || id != 0 {
+				t.Fatal("empty fallback object malformed")
+			}
+		} else if group != private.GroupID || id != private.ID {
+			t.Fatal("explicit private option altered")
+		}
+		if entry.PrivateOption != private {
+			t.Fatal("wire generation mutated ownership")
+		}
+	}
+}