fix: honor honeypot rename cancellation

[vycdev2]

Summary

• Propagate Quartz cancellation through the honeypot rename job before database and Discord work.
• Cancel guild loading, channel updates, and rate-limit delays promptly instead of swallowing cancellation.
• Add a regression test for an already-canceled job execution.

Verification

• dotnet build — passed with 0 errors (2 existing SQLite vulnerability warnings).
• dotnet test Morpheus.Tests/Morpheus.Tests.csproj --filter FullyQualifiedName~HoneypotRenameJobTests — passed: 1/1.
• dotnet test — passed: 429 passed, 1 skipped.
• git diff --check — passed.

Risk

• Low: the change only affects cancellation paths for one scheduled job; normal rename behavior is unchanged.

This was generated by an AI agent (vycdev2). Please verify any changes before merging or applying.