Resolve "Add Category Based Sorting Functionality" (GitLab Duo Enabled)

This code change adds a new feature that allows users to browse products by category on the website.

The main additions include:

• A new web page route that displays products filtered by a specific category (like "Clothing" or "Accessories")
• A database function that searches through all products and returns only those matching a requested category, with smart case-insensitive matching
• Error handling that shows a helpful message and redirects users if no products are found in the requested category
• Comprehensive testing to ensure the category filtering works correctly with different inputs, handles edge cases like empty searches, and maintains data integrity

The feature makes it easier for customers to find what they're looking for by organizing products into logical groups, improving the overall shopping experience on the site.