virtualenv: Generated files can follow existing destination links
Generated activation files and pyvenv.cfg can follow existing links and write outside the requested environment. The template writer tests exists() before unlinking, which misses dangling symlinks; the configuration writer opens the existing path directly. Anthropic's OSS Scanner reported this as ANT-2026-XBEOCBS1 in virtualenv-20261015-005, received on 15 October 2026.