Cursor-mode finger-drag on a shape in <Fresco.scroll_strip> now
moves the shape instead of scrolling the page. Strip
`_wireStripPointerInput` adds a `touchstart` listener that hit-tests
the touch point and calls `preventDefault()` only when the finger
lands on an existing shape — defers iOS's scroll-vs-app
classification long enough for `pointerdown` + `setPointerCapture`
to claim the gesture for the move handler.

Every other tap (empty area, between pages, etc.) still scrolls,
so the reader can navigate the chapter without exiting annotation
mode. Sibling to 0.4.4's `touch-action: none` fix, scoped to
cursor mode where blanket-disabling `touch-action` would break
reader navigation. `{ passive: false }` on the listener so
`preventDefault` actually overrides the scroll classification.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>