os.homedir() reads USERPROFILE on Windows and never HOME, so the
isolation setup and every test that moved home were still resolving the
developer's real home directory. Fixtures came back empty, real sessions
leaked into counts, and the code under test wrote plans, receipts and a
sync ledger into the real ~/.config/codeburn during a run.
USERPROFILE now joins the redirected variables and a shared setHome()
helper moves HOME and USERPROFILE together; every spawn env carries both.
The remaining Windows-only failures were POSIX-shaped fixtures: chmod
tricks that only toggle a read-only attribute on NTFS, pid 1 as an
always-alive lock holder, splitting paths on '/', bare tar, mode-bit
expectations, and per-file timeouts too short for the cost of a tsx spawn.
Each gets a platform-aware equivalent so nothing is skipped on Windows and
the POSIX branches stay byte-for-byte what they were.
Full run on Windows: 267 files passed, 2 skipped, 3592 tests passed.
