Implement "Highly Recommended Products" API

[Alexandrbig1]

Priority: High
Difficulty: Intermediate
Type: Backend (Node.js + Express + MongoDB)

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Description:
We need to implement a new backend API endpoint to serve "Highly Recommended Products" for each product page.
When a user opens a product (e.g., "CoreX Whey Protein"), the frontend should fetch and display products that are contextually related to it — based on shared attributes like category, goals, or collections.

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Requirements:

• Add new route: GET /api/products/:id/recommended
• Find the product by ID
• Return up to 6 related products that share:
  • Same category, or
  • At least one matching goal, or
  • At least one matching collection
• Exclude the original product from the results
• Sort randomly or by rating
• Return an empty array if no matches found

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Acceptance Criteria:

• Endpoint works with existing MongoDB schema
• Proper error handling for invalid IDs
• Returns up to 6 valid product objects
• Follows existing backend structure and coding style
• Tested via Postman or frontend call

[mdrehan369]

hello