Feature/search

[Anorme]

This PR introduces a new getDiscoverableProducts model function and refactors the getProducts controller to support dynamic product discovery via keyword search, category filtering, price range, and pagination. The query logic is modularized via buildProductQuery() in src/utils, enabling scalable and review-safe filtering across future endpoints.

Key changes:

• Added buildProductQuery() utility for layered query construction
• Introduced getDiscoverableProducts() and countDiscoverableProducts() model functions
• Refactored getProducts() controller to support search, filter, and pagination
• Preserved legacy pagination functions for backward compatibility