Goodreads import fix, custom docs domain and isbn uniqueness fix

[codebude]

This pull request implements a significant change to ISBN uniqueness, making it enforced per user rather than globally, and migrates all documentation URLs and related configuration from the old GitHub Pages domain to the new custom domain docs.librislog.app. It also improves test coverage for user data isolation, updates analytics and version check endpoints, and makes minor workflow and import improvements.

Book ISBN uniqueness and user data isolation:

• The Book model and database schema now enforce ISBN uniqueness per user instead of globally. This is achieved by adding a composite unique constraint on (user_id, isbn) and updating the migration logic to handle the transition both forwards and backwards. Error handling for unique constraint violations is updated accordingly. [1] [2] [3] [4]
• Added comprehensive tests to ensure that two users can each have a book with the same ISBN, and that all book operations (list, get, update, delete, stats, suggestions) are properly isolated by user.

Documentation and site domain migration:

• All documentation links, badges, and references in README.md, developer guides, and frontend/backend configs are updated to use https://docs.librislog.app/ (and /next/ for nightly docs) instead of the old codebude.github.io/librislog URLs. [1] [2] [3] [4] [5] [6]
• Documentation site configuration (docs/.vitepress) is updated for the new domain, including analytics, base paths, and navigation links. [1] [2] [3]
• The docs build workflow now writes a CNAME file to support the custom domain.

Workflow and CI improvements:

• The tests workflow now grants issues: write permission and only posts PR comments if the PR originates from the same repository, avoiding errors on forks. [1] [2]

Import and data handling improvements:

• The Goodreads import now correctly transforms review notes to preserve line breaks, and recognizes the "did-not-finish" shelf as a valid status. [1] [2]

[github-actions]

🧪 Test Results — 73b1ac2

✅ Backend (pytest) — 709 passed, 0 failed, 0 skipped (709 total)
✅ CLI (pytest) — 54 passed, 0 failed, 0 skipped (54 total)
✅ Frontend (vitest) — 375 passed, 0 failed, 0 skipped (375 total)
✅ E2E (Playwright) — 54 passed, 0 failed, 0 skipped (54 total)

Summary: ✅ All 1192 tests passed