DLL reference mismatch with the new Unity AI Assistant package

[rkroska]

Summary of what happened:

Unity 6.3 upgrade changed how System.Collections.Immutable was handled
Unity AI Assistant package was causing version conflicts (had v10, MCP needed v9)
After removing AI Assistant, Unity had v8 but MCP's CodeAnalysis dependency needed v9
Installing System.Collections.Immutable v9.0.0 in Assets/Plugins/ resolved everything

[BlindsidedGames]

@dsarno I am pretty sure I didn't fix this, not sure why claude mentioned it my bad sorry.

[Scriptwonder]

@rkroska, what do you preinstall besides Unity-MCP to find this error? Would be great to know if there is a fix on our side.