[CHORE] [ui] Heading order and landmark audit across all fifteen routes

[determined-001]

Description
The redesign moved headings on several pages, and one Playwright spec caught a heading that no longer exists. Nothing verifies heading order or landmark structure anywhere.
Requirements

• Check each of the fifteen routes for a single h1, no skipped levels, and correct landmarks.
• Fix what is wrong and add a test that asserts the rule rather than the current output.

Acceptance Criteria

• A test fails if a page grows a second h1 or skips a level.

Estimated File Changes: 6 (page files, a test)

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Filed from batch-readiness.md · R30

[QwinDivy]

@QwinDivy has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Maintainer, I’m happy to take this one. After reviewing the codebase, I’m comfortable with the proposed approach and ready to get started. I’ll keep the scope focused, add solid test coverage, and ensure CI stays green. I’d be glad to open a draft early so we can confirm the direction together.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @QwinDivy to this issue.

[drips-wave]

Congratulations, @QwinDivy! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

🧑‍💻 @QwinDivy: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

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