* upstream/main: (252 commits)
  Move Watch EA to a separate assembly Microsoft.CodeAnalysis.ExternalAccess.HotReload (dotnet#80556)
  Enable long paths for Windows DartLab CI (dotnet#80581)
  Ensure that CS8659 is reported on partial properties (dotnet#80573)
  Fix a wrong relative link in a doc (dotnet#80567)
  [main] Source code updates from dotnet/dotnet (dotnet#80578)
  Update dependencies from https://github.com/dotnet/arcade build 20251006.2 (dotnet#80577)
  Update main configs after VS snap (dotnet#80523)
  Add followup async public apis (dotnet#80455)
  Reduce allocations in CSharpSyntaxNode.GetStructure (dotnet#80562)
  Extensions: Close some tracked follow-ups (dotnet#80527)
  Fix outdated 17.15 to 18.0 (dotnet#80570)
  Update dependencies from https://github.com/dotnet/dotnet build 285582 (dotnet#80551)
  Fix all-in-one tests
  [main] Update dependencies from dotnet/arcade (dotnet#80559)
  Improve error recovery when object initializer uses ':' instead of '=' (dotnet#80553)
  Support `field` keyword in EE. (dotnet#80515)
  Log a debug message for ContentModified exceptions. (dotnet#80549)
  Update dependencies from https://github.com/dotnet/arcade build 20251002.2 (dotnet#80550)
  Fix
  Simplify and add additional asserts
  ...