[Gear] Hex Lord's Dooming Idol

[taherbert]

Implements the 12.1 trinket Hex Lord's Dooming Idol (270169).

• Equip (1295884): spell casts stack a self int drain (1307470), 6s ICD, up to 30 stacks
• Use (1295885): consumes the stacks, granting int per stack consumed for 30s

Follows the Spymaster's Web structure, including fallback buffs so APLs can reference hex_lords_doom / hex_lords_dooming_idol without the item equipped. The on-use buff is named hex_lords_dooming_idol since the drain and the payoff share a spell name.