feat: parse SMSG_GMTICKET_GETTICKET/SYSTEMSTATUS and SMSG_SPELLINSTAKILLLOG

Previously SMSG_GMTICKET_GETTICKET and SMSG_GMTICKET_SYSTEMSTATUS were
silently consumed. Now both are fully parsed:
- SMSG_GMTICKET_GETTICKET decodes all four status codes (no ticket,
  open ticket, closed, suspended), extracts ticket text, age and
  server-estimated wait time, and stores them on GameHandler.
- SMSG_GMTICKET_SYSTEMSTATUS shows a chat message when GM support
  goes offline/online.
- Added requestGmTicket() (sends CMSG_GMTICKET_GETTICKET) called
  automatically when the GM Ticket UI window is opened, so the player
  sees their existing open ticket text and wait time on first open.
- GM Ticket UI window now shows current-ticket status bar, estimated
  wait time, and hides the Delete button when no ticket is active.

Also implements SMSG_SPELLINSTAKILLLOG (previously silently consumed):
parses caster/victim/spellId for all expansions and emits combat text
when the local player is involved in an instant-kill spell event (e.g.
Execute, Obliterate).

include/game/game_handler.hpp

@@ -494,6 +494,13 @@ public:
     // GM Ticket
     void submitGmTicket(const std::string& text);
     void deleteGmTicket();
+    void requestGmTicket();          ///< Send CMSG_GMTICKET_GETTICKET to query open ticket
+
+    // GM ticket status accessors
+    bool hasActiveGmTicket() const { return gmTicketActive_; }
+    const std::string& getGmTicketText() const { return gmTicketText_; }
+    bool isGmSupportAvailable() const { return gmSupportAvailable_; }
+    float getGmTicketWaitHours() const { return gmTicketWaitHours_; }
     void queryGuildInfo(uint32_t guildId);
     void createGuild(const std::string& guildName);
     void addGuildRank(const std::string& rankName);
@@ -3021,6 +3028,12 @@ private:
 
     // ---- Quest completion callback ----
     QuestCompleteCallback questCompleteCallback_;
+
+    // ---- GM Ticket state (SMSG_GMTICKET_GETTICKET / SMSG_GMTICKET_SYSTEMSTATUS) ----
+    bool        gmTicketActive_    = false;  ///< True when an open ticket exists on the server
+    std::string gmTicketText_;               ///< Text of the open ticket (from SMSG_GMTICKET_GETTICKET)
+    float       gmTicketWaitHours_ = 0.0f;  ///< Server-estimated wait time in hours
+    bool        gmSupportAvailable_ = true; ///< GM support system online (SMSG_GMTICKET_SYSTEMSTATUS)
 };
 
 } // namespace game

include/ui/game_screen.hpp

@@ -438,7 +438,8 @@ private:
     void  renderEquipSetWindow(game::GameHandler& gameHandler);
 
     // GM Ticket window
-    bool  showGmTicketWindow_ = false;
+    bool  showGmTicketWindow_     = false;
+    bool  gmTicketWindowWasOpen_  = false; ///< Previous frame state; used to fire one-shot query
     char  gmTicketBuf_[2048] = {};
     void  renderGmTicketWindow(game::GameHandler& gameHandler);