Google Search Console reports 'Alternate page with proper canonical tag' for URLs with tracking query params (?ref=producthunt, ?ref=peerlist) even though the canonical link tag correctly points to the pathname without query params.
A canonical link tag alone is a hint — Google may still index parameterized URLs as alternates. Add a SvelteKit server hook that 301-redirects URLs containing tracking query params (ref, utm_source, utm_medium, utm_campaign, utm_term, utm_content) to the clean URL. Strip only tracking params and preserve non-tracking ones. Place the hook first in the sequence() chain to short-circuit before other processing. A 301 redirect is authoritative and tells Google definitively these are the same page.