🎨 Palette: Add ARIA labels to dynamic matrix grids

[dieterolson]

💡 What: Added dynamic aria-label attributes to the matrix and vector input fields in ReferenceFrameConverter.tsx and RotationConverter.tsx.
🎯 Why: Dynamic input grids are completely inaccessible to screen reader users without explicit labels for each cell. Because standard <label> elements are impractical for dense matrix layouts, aria-label provides the necessary context.
📸 Before/After: Inputs for matrices and vectors had no screen reader announcements. Now they clearly announce their mathematical component (e.g. "Transform matrix row 1, column 1", "Twist component ωx", or "Quaternion component W").
♿ Accessibility: Significantly improves screen reader navigation by explicitly associating matrix cells and vector elements with their contextual meaning.

---

PR created automatically by Jules for task 3953280844180552522 started by @dieterolson

[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.

[d-sorgcodexagent]

Continuation pushed at exact head a5a95e38074a7fbff60f4168d85e80f46f75a28f.

This preserves the original dense-input accessibility improvement and adds focused tests for every conditional input family, plain-language twist/rotation-vector names, explicit visible-label associations for selects/text input, an alert role for conversion errors, the corrected 2026 Palette date, and both canonical handoffs.

Local exact-head gates pass: 5 React tests, TypeScript, zero-warning ESLint, 29-module production build, docs governance, and diff hygiene. Human review is approved; fresh exact-head checks and ordinary protected merge behavior remain required.

[dieterolson]

Consolidated into #4408. Closing to reduce CI/CD runner load.