[Kalshi] Optimization: Implement server-side search/sort

[realfishsam]

Currently, the Kalshi implementation for fetchMarkets (sorting) and searchMarkets (filtering) is entirely client-side. Because the Kalshi V2 API relies on cursor-based pagination and lacks global sorting/search parameters for the /events endpoint, the library is forced to:

1. Sequentially fetch multiple pages of data.
2. Flatten the nested event/market structure.
3. Perform .sort() or .filter() in JavaScript.

Impact:

• High latency for search queries compared to Polymarket (which supports server-side sorting via Gamma).
• High number of API requests to fetch a comprehensive list of markets.

Goal:

• Track Kalshi API documentation for any updates to search/sort capabilities.

[realfishsam]

wontfix until Kalshi fixes their API.