Add Clan Wars Free-For-All (Safe & Dangerous) portals

Summary

• Implement entry and exit portals for both FFA Safe and FFA Dangerous arenas
• Both portals share the same warning interface (id 793), with varbit 5279 selecting which text the client displays
• Warning dismiss preferences are stored independently per portal and integrate with the Doomsayer system
• Safe arena keeps items on death, dangerous arena drops items on death
• PvP is enabled only inside the fighting areas, with the Clan Wars overlay shown across both arenas
• Challenge portal (purple) shows an "under construction" message
• Tested in-game end-to-end

Bug fixes & Improvements

• Dragon claws special attack.
• Dark bow can now shoot dragon arrows.
• Fixed game crash in the Fight Caves minigame.
• Fixed a bug with character account creation
• Bank tab creation via drag-and-drop was silently ignored because the interfaceSwap handler only matched on fromId, causing the generic inventory swap handler to intercept the event instead.
• Collapsing a tab with more than two rows of items crashed the client because shiftToFreeIndex generated O(N*M) intermediate inventory updates in a single packet. Replaced with a single-pass bulk rearrangement.