fix(ui): start pointer drags only while the primary button is held (#1071)

On macOS, with an editable element focused and an input method active, WebKit can deliver a tap as pointerup then pointerdown, so drag trackers saw every later pointermove as a held button: one tap plus a pointer move started a phantom drag (file drag label, tab detach, tool window move) and the next tap dropped it. A drag now starts only from a move with the primary button down, a move without it cancels the press, and late button-less moves after a drag started are ignored so the drop is kept. Resizers, dialog drag/resize, pan and the review gutter end instead; the Project view also listens for pointercancel.

Refs #760

Co-authored-by: ntbang0901 <[email protected]>

src/ui/Dialog.tsx

@@ -299,6 +299,7 @@ function DialogInner({
     const rect = el.getBoundingClientRect();
     const base = { left: rect.left - offset.x, top: rect.top - offset.y };
     const move = (ev: globalThis.PointerEvent) => {
+      if (!(ev.buttons & 1)) return up();
       // Keep the title bar reachable.
       const x = Math.min(
         Math.max(ev.clientX - start.x, -base.left - rect.width + 80),
@@ -331,6 +332,7 @@ function DialogInner({
     const minH = chrome + 120;
     const origin = offset;
     const move = (ev: globalThis.PointerEvent) => {
+      if (!(ev.buttons & 1)) return up();
       const w = Math.min(Math.max(rect.width + ev.clientX - start.x, minW), window.innerWidth - 24);
       const h = Math.min(Math.max(rect.height + ev.clientY - start.y, minH), window.innerHeight - 24);
       setSize({ w, h });