fix: pin cron jobs to UTC

[vycdev2]

Summary

• Pin every Quartz cron schedule to UTC so host timezone changes cannot shift daily bot avatar, honeypot rename, UBI, or wealth-tax execution times.
• Add a regression test that resolves each configured cron trigger and verifies its timezone.

Verification

• dotnet build — passed: 0 errors; 2 existing NU1903 dependency warnings.
• dotnet test --no-build --filter 'FullyQualifiedName~BotStartupExtensionsTests' --logger 'console;verbosity=minimal' — passed: 1/1.
• dotnet test --no-build --logger 'console;verbosity=minimal' — 298 passed, 2 failed: the same pre-existing tr-TR culture cases fail on synced develop because this runner uses globalization-invariant mode.
• git diff --check upstream/develop...HEAD — passed.

Risk

• Low — this makes existing cron expressions deterministic across deployment hosts without changing their documented clock times.

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