Verify: migrate from Valkey to KiviDB

Use the verify script from the Redis guide. It compares key counts, and each key's type, value, TTL, hash field expiry and stream consumer groups:

Use the verify script from the Redis guide. It compares key counts, and each key's type, value, TTL, hash field expiry and stream consumer groups:

python3 verify.py redis://:$VALKEY_PASSWORD@valkey.internal:6379 \
  redis://:$KIVIDB_PASSWORD@kividb.internal:6380 0 0 1

Valkey 8 has no field expiry and answers HPEXPIRETIME with an error; the script then checks that KiviDB has none set either.