fix: SMSG_IGNORE_LIST read phantom string field after each GUID

The packet only contains uint8 count + count×uint64 GUIDs, but the
handler called readString() after each GUID. This consumed raw bytes of
subsequent GUIDs as a string, corrupting all entries after the first.
Now stores GUIDs in ignoreListGuids_ and resolves names asynchronously
via SMSG_NAME_QUERY_RESPONSE, matching the friends list pattern.

Also fixes unsafe static_pointer_cast in ready check (no type guard)
and removes redundant packetHasRemaining wrapper (duplicates Packet API).

include/game/game_handler.hpp

@@ -2420,7 +2420,8 @@ private:
     std::vector<FactionStandingInit> initialFactions_;
 
     // ---- Ignore list cache ----
-    std::unordered_map<std::string, uint64_t> ignoreCache;  // name -> guid
+    std::unordered_map<std::string, uint64_t> ignoreCache;  // name -> guid (UI display)
+    std::unordered_set<uint64_t> ignoreListGuids_;            // authoritative GUID set from server
 
     // ---- Logout state ----
     bool  loggingOut_        = false;