feat: Add UniqueGift type with related fields and constants

tgbotapi.core/src/commonMain/kotlin/dev/inmo/tgbotapi/types/Common.kt

@@ -671,6 +671,12 @@ const val edgeColorField = "edge_color"
 const val symbolColorField = "symbol_color"
 const val textColorField = "text_color"
 
+const val baseNameField = "base_name"
+const val numberField = "number"
+const val modelField = "model"
+const val symbolField = "symbol"
+const val backdropField = "backdrop"
+
 const val businessConnectionIdField = "business_connection_id"
 const val businessIntroField = "business_intro"
 const val businessLocationField = "business_location"

tgbotapi.core/src/commonMain/kotlin/dev/inmo/tgbotapi/types/UniqueGift.kt

@@ -0,0 +1,30 @@
+package dev.inmo.tgbotapi.types
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+/**
+ * This object describes a unique gift that was upgraded from a regular gift.
+ *
+ * @param baseName Human-readable name of the regular gift from which this unique gift was upgraded
+ * @param name Unique name of the gift. This name can be used in `https://t.me/nft/...` links and story areas
+ * @param number Unique number of the upgraded gift among gifts upgraded from the same regular gift
+ * @param model Model of the gift
+ * @param symbol Symbol of the gift
+ * @param backdrop Backdrop of the gift
+ */
+@Serializable
+data class UniqueGift(
+    @SerialName(baseNameField)
+    val baseName: String,
+    @SerialName(nameField)
+    val name: String,
+    @SerialName(numberField)
+    val number: Int,
+    @SerialName(modelField)
+    val model: UniqueGiftModel,
+    @SerialName(symbolField)
+    val symbol: UniqueGiftSymbol,
+    @SerialName(backdropField)
+    val backdrop: UniqueGiftBackdrop
+)