* fix(studio): fall back to copy when os.replace is blocked during install activation
On Windows ARM64 the antivirus scanner can transiently hold a freshly
extracted DLL open while MoveFileEx runs, so activating the staged
llama.cpp prebuilt fails with [WinError 5] Access is denied. Attempt
os.replace first, then fall back to a file-by-file copytree which
bypasses the rename.
* address review: keep os.replace for rollback, scope copy-fallback to staging
The copy + rmtree fallback could silently corrupt a live install if the
existing directory is busy. Restrict it to freshly extracted staging
trees (renamed activate_staged_dir) and keep strict os.replace for the
rollback move so a busy active install raises immediately.
* fix(studio): scope copy-fallback to busy-lock errors, log it, and add tests
---------
Co-authored-by: Lee Jackson <130007945+Imagineer99@users.noreply.github.com>
Co-authored-by: Etherll <61019402+Etherll@users.noreply.github.com>
a22169941d