fix(plugins/test): skip TestLocalResolver_BubblesUpCopyFailure when running as root
Fixes issue #87: the test sets chmod(dst, 0o555) to make the
destination read-only and asserts the copy fails. On Linux, root
bypasses filesystem permissions and can write to 0o555 directories,
so the copy succeeds when running as root and the assertion fails.
Fix: check os.Getuid() == 0 at the start of the test and skip with
a clear message. Mirrors the existing skip in
TestLocalResolver_CopyFileSourceUnreadable (line 175) which already
handles the same root-bypass issue for unreadable source files.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>