fix: harden resp-compat client setup for Eloq e2e

[starrysky9959]

Summary

• add an Eloq-specific resp-compat wrapper that forces RESP2 for redis-py clients
• preserve local e2e TLS compatibility for resp-compat when --ssl is enabled
• discover the current primary from CLUSTER SLOTS before running resp-compat so tests do not target the standby node

Validation

• rebuilt the resp-compat docker image locally
• verified standalone and cluster clients can both connect with redis 8.0.0 when protocol=2 is forced
• verified the resp-compat script now progresses into real test execution instead of failing during client initialization