feat: implement barber shop UI with hair/facial customization

Adds a functional barber shop window triggered by SMSG_ENABLE_BARBER_SHOP.
Players can adjust hair style, hair color, and facial features using
sliders bounded by race/gender max values. Sends CMSG_ALTER_APPEARANCE
on confirm; server result closes the window on success. Escape key
also closes the barber shop.

include/game/game_handler.hpp

@@ -1219,6 +1219,12 @@ public:
     uint32_t getPetUnlearnCost() const { return petUnlearnCost_; }
     void confirmPetUnlearn();
     void cancelPetUnlearn() { petUnlearnPending_ = false; }
+
+    // Barber shop
+    bool isBarberShopOpen() const { return barberShopOpen_; }
+    void closeBarberShop() { barberShopOpen_ = false; }
+    void sendAlterAppearance(uint32_t hairStyle, uint32_t hairColor, uint32_t facialHair);
+
     /** True when ghost is within 40 yards of corpse position (same map). */
     bool canReclaimCorpse() const;
     /** Seconds remaining on the PvP corpse-reclaim delay, or 0 if the reclaim is available now. */
@@ -2983,6 +2989,9 @@ private:
     uint64_t activeCharacterGuid_ = 0;
     Race playerRace_ = Race::HUMAN;
 
+    // Barber shop
+    bool barberShopOpen_ = false;
+
     // ---- Phase 5: Loot ----
     bool lootWindowOpen = false;
     bool autoLoot_ = false;

include/game/world_packets.hpp

@@ -2796,5 +2796,12 @@ public:
     static network::Packet build(int32_t titleBit);
 };
 
+/** CMSG_ALTER_APPEARANCE – barber shop: change hair style, color, facial hair.
+ *  Payload: uint32 hairStyle, uint32 hairColor, uint32 facialHair. */
+class AlterAppearancePacket {
+public:
+    static network::Packet build(uint32_t hairStyle, uint32_t hairColor, uint32_t facialHair);
+};
+
 } // namespace game
 } // namespace wowee