Add a Sort button that orders the main bank and bank bags by quality/itemID/
stack (mirroring the backpack sort, one CMSG_SWAP_ITEM per frame), a
"Combine bags" toggle that renders every bank slot as one continuous grid,
and per-slot purchase prices from BankBagSlotPrices.dbc on the bank-bag row
(only the next slot in sequence is buyable; later ones are locked).
Share the backpack footer (Sort Bags + money) with the All Bags window, flag
quivers/ammo pouches/profession bags via Inventory::isBagSpecial so sorting
skips them, and tint/label their slots so restricted space isn't mistaken for
general-purpose slots. Also name container/quiver subclasses in tooltips.
