feat(validation): archive key result assets

Keep key validation outputs and analysis tables tracked directly,
package analysis plot PNGs into a small tar.gz backup, and add
analysis scripts plus tests so the stored results remain
reproducible without flooding git with large image trees.

pixi.toml

@@ -19,6 +19,7 @@ rdkit = ">=2025.9.1,<2026"
 pandas = ">=2.3.3,<3"
 numpy = ">=2.3.4,<3"
 matplotlib = ">=3.10,<4"
+seaborn = ">=0.13,<0.14"
 sqlmodel = ">=0.0.37,<0.0.38"
 
 [pypi-dependencies]