#688 (analytics) and #689 (transparency) each added last_scraped_at?: string|null
to AggregatedEstimate; each PR was internally consistent (tsc green in isolation),
but after BOTH merged the field was declared twice → 'Type error: Duplicate
identifier last_scraped_at' → next build failed → build-frontend red → deploy
skipped (run #535). Remove the second declaration (keep the original at the
metadata block); price_trend untouched. tsc --noEmit clean.