[SandObserver]

Summary

• Add wheelPager() to dashboard-logic.js: one page per sideways wheel or trackpad gesture, a 40px threshold and a 220ms quiet gap between gestures.
• Listen for wheel on the dashboard document (non-passive) and turn the page in reading direction; skip zoom gestures, Spotlight and an open folder in both layouts.
• Time gestures by event.timeStamp, so a busy main thread does not split one swipe into two in engines that stamp input time; forwarded frame events carry their original time.
• Cancel sideways wheel events so the browser's back and forward swipe does not fire.
• Leave sideways scrolling to any element under the pointer that scrolls sideways itself (scrollsSideways() in utils.js).
• Forward wheel events from bundled widget frames to their card, so paging also works over widgets.

Testing
All green. Added tests for the pager, scrollsSideways(), and e2e specs for paging over the dashboard, over a widget, under the phone-layout folder, and during a busy main thread.

Changelog

Added

• A sideways trackpad swipe or mouse wheel turns dashboard pages, one page per gesture.

Checklist

• Stays within the project constraints: one container, no runtime dependencies, no build step (see CONTRIBUTING.md).
• Tests added or updated for new logic, and the full suite, lint, and typechecks pass.
• Docs updated if behavior or configuration changed.