gesture: refresh PointerID on Press and Enter

Click and Hover both stored the first PointerID they observed in
their internal pid field and only updated it when not currently
hovered/entered. Once the gesture became hovered, any later event
under a different PointerID was effectively ignored: Click.Press
fell through 'c.pid != e.PointerID' and was silently dropped, and
Hover could never reset entered when the matching Leave arrived
under a new ID.

The Windows backend enables EnableMouseInPointer
(app/os_windows.go), under which Windows reassigns the same
physical mouse's PointerID across focus changes, window
leave/re-enter, and similar events. Once a widget had been hovered,
every subsequent press on it failed to register, including
widget.Editor's internal clicker that positions the caret on press.
Multi-line editors silently refused to move the caret on click
after the window had received any focus event.

Always take the latest PointerID on Hover.Enter and Click.Press.
The Press/Release handshake still works because Press now records
the press's own PointerID and Release continues to gate on
'c.pid != e.PointerID' so an unrelated pointer's release can't end
the press tracking.

Signed-off-by: Eugene <eugenebosyakov@gmail.com>

gesture/gesture.go

@@ -61,12 +61,8 @@ func (h *Hover) Update(q input.Source) bool {
 				h.entered = false
 			}
 		case pointer.Enter:
-			if !h.entered {
-				h.pid = e.PointerID
-			}
-			if h.pid == e.PointerID {
-				h.entered = true
-			}
+			h.pid = e.PointerID
+			h.entered = true
 		}
 	}
 	return h.entered
@@ -222,12 +218,7 @@ func (c *Click) Update(q input.Source) (ClickEvent, bool) {
 			if e.Source == pointer.Mouse && e.Buttons != pointer.ButtonPrimary {
 				break
 			}
-			if !c.hovered {
-				c.pid = e.PointerID
-			}
-			if c.pid != e.PointerID {
-				break
-			}
+			c.pid = e.PointerID
 			c.pressed = true
 			if e.Time-c.clickedAt < doubleClickDuration {
 				c.clicks++