CodeRabbit Generated Unit Tests: Add Jest/JSDOM unit tests for book, library, main, indexedDB, style

[coderabbitai]

Unit test generation was requested by @coderabbitai[bot].

• Migrate to Vite, add PWA/offline support, and fix table-of-contents bug (v2.1.0) #2 (comment)

The following files were modified:

• tests/unit/book.test.js
• tests/unit/indexedDB.test.js
• tests/unit/library.test.js
• tests/unit/main.test.js
• tests/unit/style.test.js

[coderabbitai]

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