fix: escape newlines in macro cfg persistence; execute all macro lines

- Macro text is now escaped (\\n, \\\\) on save and unescaped on load,
  fixing multiline macros silently truncating after the first line in
  the character config file.
- executeMacroText() runs every non-comment line of a macro body in
  sequence (WoW behaviour), replacing the firstMacroCommand() approach
  that only fired the first actionable line. The server still enforces
  one spell-cast per click; non-cast commands (target, equip, pet, etc.)
  now all execute correctly in the same macro activation.

include/ui/game_screen.hpp

@@ -278,6 +278,7 @@ private:
      * Send chat message
      */
     void sendChatMessage(game::GameHandler& gameHandler);
+    void executeMacroText(game::GameHandler& gameHandler, const std::string& macroText);
 
     /**
      * Get chat type name