fix: track visualViewport continuously during scroll lock

[sun-mota]

Alaska Airlines Pull Request

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. List any dependencies that are required for this change.

Checklist:

• My update follows the CONTRIBUTING guidelines of this project
• I have performed a self-review of my own update

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-- Auro Design System Team

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[Copilot]

Pull request overview

Updates the scroll-lock implementation in AuroFloatingUI to keep fullscreen bib positioning in sync with iOS visualViewport changes (notably during virtual keyboard interactions), preventing the bib from drifting when the viewport pans.

Changes:

• Switch from a one-time visualViewport.offsetTop adjustment to continuous tracking via visualViewport resize + scroll listeners while scroll is locked.
• Add teardown logic to remove the visualViewport listeners when unlocking scroll.
• Stop forcing .container maxHeight to visualViewport.height during fullscreen strategy setup (now resets to default instead).

---

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

scripts/runtime/floatingUI.mjs:370

• The new visualViewport tracking logic (RAF-throttled scroll/resize listeners + unlock cleanup) introduces non-trivial behavior that isn't covered by the existing lockScroll tests. Consider adding a focused unit test that stubs window.visualViewport (with add/removeEventListener + offsetTop) and verifies: (1) listeners are registered on lock, (2) transform updates are applied via RAF when scroll/resize fires, and (3) listeners + any pending RAF are cleaned up on unlock.

        if (window.visualViewport) {
          this._viewportRafId = undefined;
          this._viewportHandler = () => {
            if (this._viewportRafId !== undefined) {
              return;
            }
            this._viewportRafId = requestAnimationFrame(() => {
              this._viewportRafId = undefined;
              if (element?.bib) {
                element.bib.style.transform = `translateY(${window.visualViewport.offsetTop}px)`;
              }
            });
          };
          window.visualViewport.addEventListener(
            "resize",
            this._viewportHandler,
          );
          window.visualViewport.addEventListener(
            "scroll",
            this._viewportHandler,
          );
          this._viewportHandler();

[rmenner]

Dev release of this PR:

@aurodesignsystem-dev/auro-library@0.0.0-pr273.0

[sun-mota]

DRAFT PR for testing in auto-formkit: AlaskaAirlines/auro-formkit#1571