fix(timeline): stabilize overlay lifecycle

apps/web/src/components/timeline/TimelineView.tsx

@@ -355,6 +355,7 @@ function TimelineViewContent({
     anchorEl: HTMLElement;
   } | null>(null);
   const resourceHoverTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
+  const previousViewModeRef = useRef(viewMode);
 
   const invalidateTimelineInner = useInvalidateTimeline();
   const batchDeleteMutation = trpc.allocation.batchDelete.useMutation({
@@ -386,6 +387,26 @@ function TimelineViewContent({
     setResourceHover(null);
   }, [hasActivePointerOverlay]);
 
+  useEffect(() => {
+    if (previousViewModeRef.current === viewMode) {
+      return;
+    }
+
+    previousViewModeRef.current = viewMode;
+    setPopover(null);
+    setDemandPopover(null);
+    setNewAllocPopover(null);
+    setResourceHover(null);
+  }, [viewMode, setNewAllocPopover]);
+
+  useEffect(() => {
+    if (!isInitialLoading) return;
+    setPopover(null);
+    setDemandPopover(null);
+    setNewAllocPopover(null);
+    setResourceHover(null);
+  }, [isInitialLoading, setNewAllocPopover]);
+
   // ─── Keep selection overlay visible while popover is open ───────────────────
   const effectiveRangeState: typeof rangeState = rangeState.isSelecting
     ? rangeState

apps/web/src/hooks/useViewportPopover.ts

@@ -155,6 +155,8 @@ export function useViewportPopover({
   }, [align, anchor, estimatedHeight, offset, side, viewportPadding, width, zIndex]);
 
   useEffect(() => {
+    const closeOnViewportChange = anchor.kind === "point";
+
     function cancelScheduledFrame() {
       if (frameRef.current === null) return;
       cancelAnimationFrame(frameRef.current);
@@ -181,9 +183,19 @@ export function useViewportPopover({
     updateOrClose();
 
     const handleScroll = () => {
+      if (closeOnViewportChange) {
+        cancelScheduledFrame();
+        onClose();
+        return;
+      }
       scheduleUpdate("scroll");
     };
     const handleResize = () => {
+      if (closeOnViewportChange) {
+        cancelScheduledFrame();
+        onClose();
+        return;
+      }
       scheduleUpdate("resize");
     };