* fix: readers never see an empty or half-written project file
* test: pin the create routes and block install to whole-file writes
* fix(sdk): a write through a link to a missing file creates that file
* fix: saves through a linked folder reach the real file, atomic writes handle long names
* test(sdk): check for the stray file, not the folder listing
* fix(core): creates work on Windows FAT drives, and links through folders resolve as the system does
* fix: agree the helper move in the deletion check, and match temp paths without a path regex
* test: check POSIX file modes only off Windows