feat: implement CMSG_PET_RENAME with rename dialog in pet frame

- Add PetRenamePacket::build(petGuid, name, isDeclined) builder
- Add GameHandler::renamePet(newName) — sends packet via petGuid_
- Add 'Rename Pet' to pet frame context menu (right-click pet name)
- Modal input dialog with 12-char limit matches server validation

include/game/game_handler.hpp

@@ -609,6 +609,7 @@ public:
     void cancelCast();
     void cancelAura(uint32_t spellId);
     void dismissPet();
+    void renamePet(const std::string& newName);
     bool hasPet() const { return petGuid_ != 0; }
     uint64_t getPetGuid() const { return petGuid_; }
 

include/game/world_packets.hpp

@@ -2718,5 +2718,14 @@ public:
     static network::Packet build(uint64_t stableMasterGuid, uint32_t petNumber);
 };
 
+class PetRenamePacket {
+public:
+    /** CMSG_PET_RENAME: rename the player's active pet.
+     *  petGuid: the pet's object GUID (from GameHandler::getPetGuid())
+     *  name: new name (max 12 chars; server validates and may reject)
+     *  isDeclined: 0 for non-Cyrillic locales (no declined name forms) */
+    static network::Packet build(uint64_t petGuid, const std::string& name, uint8_t isDeclined = 0);
+};
+
 } // namespace game
 } // namespace wowee

include/ui/game_screen.hpp

@@ -434,6 +434,10 @@ private:
     char  gmTicketBuf_[2048] = {};
     void  renderGmTicketWindow(game::GameHandler& gameHandler);
 
+    // Pet rename modal (triggered from pet frame context menu)
+    bool petRenameOpen_ = false;
+    char petRenameBuf_[16] = {};
+
     // Inspect window
     bool  showInspectWindow_ = false;
     void  renderInspectWindow(game::GameHandler& gameHandler);