Fix Formulation Filter Deduplication Bug

I maintain a JavaScript/Node.js price-collector that scrapes several e-commerce sites, stores the results, and feeds them to the frontend. Most filters behave, but the one tagged “Formulation” is dropping items. Whenever two products share the same dosage yet differ in presentation—spray versus vial, for instance—only one shows up. A previous pass with Claude AI couldn’t untangle the deduplication logic, so I need fresh eyes.

You’ll inspect the current Node.js data-processing pipeline, the part that decides what counts as a duplicate, and the frontend query that renders the filter list. Your goal is to let both spray and vial (and any future variants) appear simultaneously while still blocking true duplicates.

Deliverables
• Updated deduplication or grouping routine in the scraper / API layer
• Adjusted filter query so every unique dosage + presentation combo is exposed
• Short change log explaining the fix and any schema tweaks
• Pull request or patch ready to merge

Acceptance criteria
Running a fresh scrape shows at least one product pair where both presentations surface under “Formulation,” other filters continue to work, and response times remain unaffected.