Known imports of a higher layer.
# Known imports of a higher layer (docs/package-guide.md § 1: euler_webshell → euler_site → solver).
# Format: <repo-relative path> <imported module>. Ratchets down only:
# scripts/linters/layers.py fails on a new violation AND on a line that no longer matches.
#
# Empty since phase 4. Keep it that way.