Remaining issues for "sync namespace" refactoring

[genlu]

Using this to track some of the remaining issues for the "Sync namespace" refactoring.

• Fix undo of move file
• Make this refactoring work on CPS based projects (Get root namespace from the project #30998, Upgrade the project system to depend on the latest version of Roslyn project-system#4312)
• Change of default namespace through Project Properties page is not reflected in workspace. Need to figure out how to listen to that change.
• Provide move file operation for CPS, also applies to move type refactoring. (blocked by Add an API that lets consumers wait on language service to be up-to-date with a given project version project-system#3425)
• Change namespace from global to non-global, the fix reference like global:Foo. (including cref)
• Use IProgressTracker
  [WIP] Sync namespace and folder refactoring (C#) #30156 (comment)
• Unification of C# and VB logic
• Refactor into Change namespace service (Refactor change namespace service #31447 ) and move file service (this also covers move type refactoring). Related to Move Type to Namespace refactoring #30896
• Fix tests to avoid leak of implementation details
  [WIP] Sync namespace and folder refactoring (C#) #30156 (comment)
• Offer refactoring at pos-0?
  [WIP] Sync namespace and folder refactoring (C#) #30156 (comment)
• Minor change to reduce redundant computation
  [WIP] Sync namespace and folder refactoring (C#) #30156 (comment)
• Find-all-ref w/o cascading (perf improvement)
  I would like a way to find references to a symbol, without cascading being involved. #25628
• Behavior of addimport service
  [WIP] Sync namespace and folder refactoring (C#) #30156 (comment)
• Integration test for VS workspace behavior and undo
• Sync namespace to folder reformats the entire document #34707

[CyrusNajmabadi]

@genlu do we need this tracking issue anymore? what's the plan here?