fix(seller): stop price override items from bypassing every filter

[icemansparks]

Reported: Twin Blades of Azzinoth (bind on pickup) showed up in the auction house. No BoP item should ever be listed.

Root cause

The seller has two independent sources of items, and only one of them is filtered.

• AHBConfig::InitializeBins() applies every filter — bind type, class, level, req level/skill, vendor/loot/other, conjured/gems/keys/lootable, mod_auctionhousebot_disabled_items, SellerWhiteList — and puts the survivors into the per-quality bins.
• AHBConfig::LoadPriceOverrides() loads mod_auctionhousebot_priceOverride raw, with no filtering whatsoever.
• GetItemsToSell() builds its two priority blocks by iterating config->itemPriceOverrides directly, so those items never went through the bins.
• In Sell() the only gates on such a pick are the per-item count cap, "does a prototype exist", and Quality > AHB_MAX_QUALITY. No bind check. No disabled-items check. No whitelist check.

Net effect: a row in the price override table was an unconditional licence to list the item. With ~11.5k override rows, that is a wide hole.

Two consequences worth calling out:

1. AuctionHouseBot.Bind_When_Picked_Up = 0 was silently ignored for every override item — the reported BoP weapon.
2. Rows added to mod_auctionhousebot_disabled_items did nothing for any item that also has a price override, so blacklisting alone could not fix it.

Fix

InitializeBins() now records every item that passed its tests in a new SellableItems set (the union of the bins — one insert at the point an item is accepted), and both priority blocks skip anything that is not in it:

if (!config->IsSellableItem(itemID))
{
    continue;
}

A price override is a price, not a permission to sell. Blocks 3 and 4 are bin-sourced and were always filtered — unchanged. Every filter now applies uniformly, and the disabled-items blacklist becomes effective on the override path too.

Verification

• Traced in code; the two priority loops were the only sell-side consumers of itemPriceOverrides (GetPriceOverrideForItem() is pricing only).
• Confirmed against the deployed config: the merkerhood config matrix sets no Bind_* overrides, so LIVE runs the .dist default Bind_When_Picked_Up = 0 — BoP was supposed to be excluded already.
• Full module compile: the core-build workflow on this PR.
• Not yet run on testcore (worldserver there is stopped; left as found).

To see the scale of what was leaking on the realm:

SELECT i.entry, i.name, i.Quality, i.bonding
FROM mod_auctionhousebot_priceOverride p
JOIN item_template i ON i.entry = p.item
WHERE i.bonding = 1
ORDER BY i.Quality DESC, i.name
LIMIT 50;

Everything that query returns is what the bot could previously list and can no longer list.

Cleanup after merge

Auctions already listed are unaffected by this change — they stay until they expire or sell. .ahbotoptions ahexpire <ahMapID> clears the bot's existing auctions if you want the BoP gear gone immediately rather than in up to 24 hours.