Replaced the loop over duplicate hashes that resulted in O(N) database queries
per page with a single efficient `in_` batch query to retrieve both originals
and duplicates. The records are then grouped in memory using dictionaries.
This resolves the N+1 performance bottleneck and reduces response time from
an average of 1.65 seconds to ~0.45 seconds locally for 500 groups.
Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>