feature/ux improvements

[codebude]

• Implement close on esc keypress for various dialogs (fixes [Bug] Escape does not close the sidebar #81 )
• Add cancelable book search to the import modal (implements [Feature Request] Ability to cancel a book search #82 )
• Add visually grouping of duplicate entries in "edition" groups to book import search (implements [UX] Append results from other providers even if they are "the same" #89 )

[github-actions]

🧪 Test Results — c0e350a

✅ Backend (pytest) — 993 passed, 0 failed, 0 skipped (993 total)
✅ CLI (pytest) — 54 passed, 0 failed, 0 skipped (54 total)
✅ Frontend (vitest) — 491 passed, 0 failed, 0 skipped (491 total)
✅ E2E (Playwright) — 75 passed, 0 failed, 0 skipped (75 total)

Summary: ✅ All 1613 tests passed