fix: hover card, preferences modal, timeline scroll, multi-drag

- ResourceHoverCard: add isInitialLoading to useEffect deps so
  mouseover/mouseout listeners attach after canvas mounts
- PreferencesModal: lift prefsOpen state to AppShell, render modal
  outside sidebar's backdrop-blur stacking context
- Timeline page: constrain to max-h-[100dvh] overflow-hidden so
  horizontal scrollbar is accessible without scrolling to bottom
- Multi-drag: pass selectedAllocationIds from ref at drag completion
  to prevent stale closure in onMultiDragComplete callback

Co-Authored-By: claude-flow <ruv@ruv.net>

apps/web/src/hooks/useTimelineDrag.ts

@@ -178,7 +178,7 @@ export function useTimelineDrag({
   onRangeSelected?: (info: RangeSelectedInfo) => void;
   onAllocationMoved?: (snapshot: AllocationMovedSnapshot) => void;
   onShiftClickAlloc?: (allocationId: string) => void;
-  onMultiDragComplete?: (daysDelta: number, mode: AllocDragMode) => void;
+  onMultiDragComplete?: (daysDelta: number, mode: AllocDragMode, selectedIds?: string[]) => void;
 }) {
   const [dragState, setDragState] = useState<DragState>(INITIAL_DRAG_STATE);
   const [allocDragState, setAllocDragState] = useState<AllocDragState>(INITIAL_ALLOC_DRAG);
@@ -394,7 +394,9 @@ export function useTimelineDrag({
           multiSelectRef.current = { ...multiSelectRef.current, isMultiDragging: false, multiDragDaysDelta: 0 };
 
           if (finalDelta !== 0) {
-            onMultiDragCompleteRef.current?.(finalDelta, dragMode);
+            // Pass IDs from ref to avoid stale closure in the callback
+            const ids = multiSelectRef.current.selectedAllocationIds;
+            onMultiDragCompleteRef.current?.(finalDelta, dragMode, ids);
           }
         }