Batch 4: aura quests, NPCs on high ground and auction house trips

Three fixes from the bug registry: quests whose item applies a timed aura ("Inoculation") finally complete, NPCs on a hill or tower are reached by a steeper path before being given up, and window-shopping trips to the auction house are limited.

"Inoculation": credit when the aura expires

The inoculating crystal applies a temporary aura to the owlkin; quest credit is only granted when the aura expires naturally. Characters did use the crystal, but the owlkin turned hostile and they killed it before the end: nothing counted (37 stuck reports, 6 draenei).

After a quest item whose spell applies a timed aura, the target is spared until the aura ends and the character waits nearby.
General fix: it applies to every quest of this kind.

NPCs on high ground

The "player" path avoids slopes steeper than 50° to prevent unnatural shortcuts. An NPC at the top of a steep ramp became unreachable ("Carry Your Weight", 18 attempts). On the first failure, characters now try the server path (slopes up to 60°) before giving up.

Auction house

A trip only to buy (with nothing to sell) happens at most once per hour.

Next finding: combat survival

Over the last 2 hours, self-healing classes rarely die (shaman 0.6 deaths per character, paladin 1.0) while fragile classes die a lot (warlock 9.4, rogue 7.7, hunter 7.6, mage 6.5). A combat lab now measures each class in duels on a test server to tune openers, melee-range handling, pets and target choice.

Verification

Deployed without crash; "infeasible" memories purged so affected quests are retried.