fix: strip fragments from Twitch channel URLs

[vycdev2]

Summary

• strip URL fragments before resolving or matching Twitch channel logins
• add a regression test for full Twitch channel URLs containing fragments

Verification

• dotnet test Morpheus.Tests/Morpheus.Tests.csproj --no-restore --filter FullyQualifiedName~SubscriptionsModuleTests — passed (1 test)
• dotnet build --no-restore — passed (1 pre-existing NU1903 warning)
• dotnet test --no-build --no-restore — passed (157 tests)
• git diff --check — passed

Risk

• Low: the change only extends the existing Twitch URL delimiter handling to include fragments.

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