fix: chunk application emoji listings

[vycdev2]

Summary

• split listemojis output into Discord-safe messages instead of sending one oversized reply
• preserve emoji order, repeat the list heading for context, and avoid splitting Unicode surrogate pairs
• add regression coverage for large listings and oversized entries

Verification

• dotnet test Morpheus.Tests/Morpheus.Tests.csproj --no-restore --filter FullyQualifiedName~EmojisModuleTests --logger "console;verbosity=minimal" — passed: 29/29
• dotnet build --no-restore — passed with 0 errors (one existing SQLitePCLRaw vulnerability warning)
• dotnet test --no-build --logger "console;verbosity=minimal" — passed: 430, skipped: 1
• python3 -m unittest tools.test_generate_commands_md — passed: 3/3
• git diff --check upstream/develop...HEAD — passed

Risk

• Low: this only changes how a long application-emoji listing is divided across replies; short listings retain the same content.

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