🎨 Palette: Fix semantic heading hierarchy in Latest Post card

[NickJLange]

💡 What: Fixed semantic heading hierarchy in the Latest Update card on the homepage by changing the nested <h3> tag to an <h4> tag. Added a critical UX learning about semantic headings to .Jules/palette.md.
🎯 Why: Having an <h3> immediately inside another section already introduced with an <h3> ("Latest Update") disrupts the logical document outline, creating confusing navigation for screen reader users expecting correct semantic hierarchy. Changing it to <h4> restores parity.
📸 Before/After: See attached screenshot of the correct heading placement.
♿ Accessibility: Improved semantic HTML hierarchy by ensuring headings are properly incremented, avoiding accessibility violations for screen readers.

---

PR created automatically by Jules for task 922177666261906777 started by @NickJLange

---

Summary by cubic

Fixes the semantic heading hierarchy in the homepage Latest Update card by changing the nested post title from <h3> to <h4>, aligning it under the existing <h3> and improving screen reader navigation. Adds an accessibility note to .Jules/palette.md to avoid hardcoded heading levels in reusable components.

^{Written for commit 97f922b. Summary will update on new commits.}

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.

[cubic-dev-ai]

No issues found across 2 files