Rounding before classification falsely marked 99.6 percent as exhausted and 79.6 percent as above the 80 percent warning threshold. Preserve measured fractions and cover default/custom thresholds with direct snapshot regressions.

Documentation: update the usage guide, AI snapshot contract, and Unreleased changelog. TODO parity scope is unaffected. Validation: make check passed with local optional KDE skips; focused snapshot tests pass without skips.