Adds missing test coverage for fields and logic introduced in PR #3 (…

[atao2004]

Summary

Adds missing test coverage for fields and logic introduced in PR #3 (ValkeyMemory implementation).

Changes

• tests/test_valkey_memory.py
  • Config tests now assert username and use_tls parsing (both defaults and explicit values)
  • test_field_specs_defined includes the new fields
  • New TestValkeyMemoryConnectionOptions — verifies use_tls and username are forwarded to _make_client
  • New TestValkeyMemorySanitizeTag — 6 tests covering _sanitize_tag() (commas, braces, spaces, pipes, empty, clean input)
  • Test helpers (_make_store, _make_valkey_memory) updated to support username, password, and use_tls params

Testing

• 55 tests pass (up from 47), 0 failures
• Full suite: 109 passed, 0 regressions

[edlng]

lgtm!