Unittest

A coding agent found a bug mid-refactor and parked it as a known issue with `@unittest.expectedFailure`. Two `git log -S` runs showed nobody had ever decided it, so it was fixed the same night. The obvious `.extend()` fix would have broken an alias. Includes the skill that does the dating.

An upload classifier sent a language model the first page of each PDF. The helper indexed a dataclass like a list, the TypeError was caught and turned into an empty string, and for seven weeks the model classified every PDF by filename alone, with a confidence score attached.