feat(timeline): add pulse animation for in-flight drag mutations

Allocation bars that have active optimistic overrides (post-drag,
awaiting server confirmation) now pulse subtly via animate-pulse.
The pending set is derived from the existing optimisticAllocations
map keys, requiring no additional state.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

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

@@ -51,7 +51,7 @@ export function AllocationPopover({
   const allocationQuery = trpc.allocation.getAssignmentById.useQuery(
     { id: allocationId },
     {
-      staleTime: 0,
+      staleTime: 10_000,
       enabled: shouldLoadAllocation,
       retry: false,
     },