Fix offline player identity lookups

[remdui]

What changed

• restore persisted DataRegistry identity fallback after active-cache misses
• keep active player lookups cache-first
• resolve known offline players by UUID, case-insensitive username, and player ID
• add regression coverage for offline and missing identities
• bound compatibility lookups to three seconds and preserve interruption state

Root cause

The recent asynchronous DataRegistry migration changed PlayerReferenceResolver to read only findActiveIdentityCached(...) and snapshotActiveIdentities(). Offline players are intentionally absent from those active snapshots. Votifier therefore treated a known offline voter as unknown and returned before recording statistics or publishing the Redis reward event.

Other affected features

Because the resolver is shared, the same regression affected offline sanctions, friend targeting, 2FA identifier lookup, settings/persistence operations that resolve an existing UUID, and historical username display by player ID. The central fallback fixes these callers without duplicating feature-specific lookup code.

Validation

• CI Lint / Checkstyle: passed
• CI Tests and Coverage / Maven Verify: passed
• regression tests cover cache hits, persisted offline UUID/name/ID lookups, missing identities, and scalar-ID fallback