Add end-to-end tests for table of contents navigation

[conico974]

Introduce end-to-end tests to verify the visibility and functionality of expandable sections in the table of contents. These tests ensure that navigation links appear as expected when sections are expanded.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 65516e2

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[github-actions]

Summary of the deployments:

Version	URL	Status
Vercel	https://gitbook-v2-pw8rgh9wl-gitbook.vercel.app	✅
Cloudflare	https://7d64f8db-gitbook-open-v2-preview.gitbook.workers.dev	✅

Test content

Site	2v	2c
GitBook	https://gitbook-v2-pw8rgh9wl-gitbook.vercel.app/url/gitbook.com/docs	https://7d64f8db-gitbook-open-v2-preview.gitbook.workers.dev/url/gitbook.com/docs
E2E	https://gitbook-v2-pw8rgh9wl-gitbook.vercel.app/url/gitbook.gitbook.io/test-gitbook-open	https://7d64f8db-gitbook-open-v2-preview.gitbook.workers.dev/url/gitbook.gitbook.io/test-gitbook-open

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Build	Status	Details	Updated (UTC)
customers-v2 (Inspect)	✅ No changes detected	-	Oct 21, 2025, 10:03 AM
v2-cloudflare (Inspect)	👍 Changes approved	4 added	Oct 21, 2025, 10:06 AM
v2-vercel (Inspect)	👍 Changes approved	2 changed, 4 added	Oct 21, 2025, 10:05 AM