Fix Typesense query limit violations and filter syntax issues

[magazine233]

• dashboard-content.html: Fix fragment lookup to use page_url filter directly instead of keyword search, ensuring correct fragments display for each page
• dashboard-platform.html: Reduce per_page from 1000 to 250 (Typesense max), fix array filter syntax (site_hierarchy:X not site_hierarchy:=X), change deduplication from title-based to page_url-based
• dashboard-topic.html: Reduce per_page from 500 to 250
• fragments-visual.html: Reduce per_page from 500 to 250
• dashboard-unified.html: Fix filter syntax escaping for life_events filter

These fixes resolve 422 "Unprocessable Entity" errors caused by exceeding Typesense's 250 per_page maximum limit.

[magazine233]

Hey Poss, typesense error 422. Troubleshooted my way though to get resolve it. Passed the repo updates from EC2 to local and synced to keep concerns separate. Cheers,