Keep long-form fixtures to known reading

[isomorphisms]

Corrects the long-form fixture selection after #53.

The fixture set is for material the maintainer actually knows well enough to judge, not a grab bag of public-domain classics.

This change:

• keeps Njál's Saga;
• restores The Adventures of Sherlock Holmes as a whole-collection fixture because the maintainer has read enough Holmes for that collection to be useful judgment material;
• removes The Hound of the Baskervilles, Frankenstein, Dracula, Moby-Dick, War and Peace, and Pride and Prejudice from the public-domain manifest because they were not established as good current judgment fixtures;
• records that Moby-Dick was read too long ago to be a good current judgment fixture;
• records known-reading cases that are copyrighted and therefore should only be exercised from user-owned/local representations: Christ Stopped at Eboli, works by Leonardo Sciascia, Musashi, and A Free Life;
• makes public-domain status a source/legal constraint rather than the selection criterion.

No browser machinery or copyrighted text is added.