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.test.tsx

@@ -120,7 +120,7 @@ describe("Dialog chrome", () => {
     down(dialog.querySelector("div:last-child")!, 10);
     expect(dialog.style.translate).toBe("");
     down(handle, 10);
-    fireEvent.pointerMove(window, { clientX: 200, clientY: 40 });
+    fireEvent.pointerMove(window, { buttons: 1, clientX: 200, clientY: 40 });
     fireEvent.pointerUp(window);
     expect(dialog.style.translate).toBe("190px 30px");
   });
@@ -134,12 +134,12 @@ describe("Dialog chrome", () => {
     const dialog = screen.getByRole("dialog");
     const bar = document.querySelector("[data-dialog-titlebar]") as HTMLElement;
     fireEvent.pointerDown(bar, { button: 0, clientX: 10, clientY: 10 });
-    fireEvent.pointerMove(window, { clientX: 60, clientY: 40 });
+    fireEvent.pointerMove(window, { buttons: 1, clientX: 60, clientY: 40 });
     fireEvent.pointerUp(window);
     expect(dialog.style.translate).toBe("80px 30px");
     // The close button never starts a drag.
     fireEvent.pointerDown(within(bar).getByRole("button", { name: "Close" }), { button: 0, clientX: 10, clientY: 10 });
-    fireEvent.pointerMove(window, { clientX: 200, clientY: 40 });
+    fireEvent.pointerMove(window, { buttons: 1, clientX: 200, clientY: 40 });
     fireEvent.pointerUp(window);
     expect(dialog.style.translate).toBe("80px 30px");
   });