[Trade Site] Add Numerical Amount Filter for Inscribed Ultimatum Rewards

Current trade site functionality for Inscribed Ultimatums allows filtering by reward type (e.g., Divine Orb) but lacks a quantitative filter for the Reward Amount.

The Problem:
Users searching for high-value Ultimatums (e.g., rewarding 1,4 or 8 Divine Orbs) must manually scroll through hundreds of "1 Divine Orb" results. While a workaround exists using "Requires Sacrifice" stat filters, it is not intuitive and is missing from the dedicated "Ultimatum Filters" section.

Requested Solution:

Add a "Reward Amount" numerical (Min/Max) field to the Ultimatum Filters category.

Alternatively, expose the "Doubles sacrificed Currency" implicit as a searchable stat with a numerical value.

Impact:
This change would significantly reduce friction for players engaging with high-end Ultimatum trading and bring the trade site's functionality in line with other league-specific filters (like Heist or Sanctum).