feat(DeviceDetailOverlay): add swipe indicator dots for device navigation

src/app/components/DeviceDetailOverlay.tsx

@@ -455,6 +455,23 @@ export default function DeviceDetailOverlay({
               ))}
             </Swiper>
           </div>
+
+          {/* ── Swipe indicator dots ── */}
+          {devices.length > 1 && (
+            <div className="flex-shrink-0 flex items-center justify-center gap-2.5 py-2 border-t border-neutral-200/50">
+              {devices.map((_, i) => (
+                <button
+                  key={i}
+                  onClick={() => swiperRef.current?.slideTo(i)}
+                  className={`rounded-full transition-all duration-200 ${
+                    activeIndex === i
+                      ? 'w-4 h-2 bg-blue-500'
+                      : 'w-2 h-2 bg-neutral-300 hover:bg-neutral-400'
+                  }`}
+                />
+              ))}
+            </div>
+          )}
         </motion.div>
       </div>
     </AnimatePresence>