fix pthash memory estimate#97
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estimate_num_bytes_for_construction returned max(map_bytes, search_bytes), but the input hash vector lives across both phases. The partitioned external builder pushes the per-partition hashes (num_keys * sizeof(hash_type)) into in_memory_partitions and only adds the build estimate to its running 'bytes' counter, so the bytes < config.ram gate underestimated true residency by num_keys * sizeof(hash_type) per partition. For hash128 (16B) plus the search-phase peak (~25B/key), peak per- partition residency is ~41B/key while the gate believed ~25B/key, so config.ram=2GiB actually allowed ~3.2GB resident. Adding the input hashes outside the max makes config.ram match observed RSS.
The previous commit added the input hashes outside the max with the correct sizeof(hash_type), so the pre-existing num_keys * sizeof(uint64_t) term inside num_bytes_for_search was double-counting.
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