Feed text search used plain ILIKE, which is case- but not diacritic-insensitive, so 'tiesto'
missed the many titles spelled 'Tiësto' — a search that ingested ~45 results showed only ~12.
Enable the postgres unaccent extension (migration 0029) and wrap both sides of the title/
channel match in unaccent(), so 'tiesto' now matches 'Tiësto'. Applies to feed, count and
facets alike.
