fix(timeline): stabilize popovers on internal scroll + expand test coverage

B-1: useViewportPopover — ignoreScrollContainers option; scroll events
originating inside the timeline canvas no longer close point-anchor popovers
B-2: AllocationPopover, DemandPopover, NewAllocationPopover — thread
scrollContainerRef through so horizontal timeline scroll is ignored
B-3: AllocationPopover — staleTime 0 so SSE reconnect triggers immediate refetch
B-4: useViewportPopover.test.ts — 6 new tests (scroll close, ignore container,
resize close, style clamping)
B-5: AllocationPopover.test.tsx — loading state + happy-path tests added

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

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

@@ -1,6 +1,6 @@
 "use client";
 
-import React from "react";
+import React, { type RefObject } from "react";
 import { clsx } from "clsx";
 import { useEffect, useState } from "react";
 import { createPortal } from "react-dom";
@@ -21,6 +21,7 @@ interface AllocationPopoverProps {
   anchorX: number;
   anchorY: number;
   contextDate?: Date;
+  ignoreScrollContainers?: RefObject<HTMLElement | null>[];
 }
 
 type AllocationPopoverAssignment = Assignment<AllocationLike>;
@@ -34,6 +35,7 @@ export function AllocationPopover({
   anchorX,
   anchorY,
   contextDate,
+  ignoreScrollContainers,
 }: AllocationPopoverProps) {
   const utils = trpc.useUtils();
   const invalidateTimeline = useInvalidateTimeline();
@@ -42,13 +44,14 @@ export function AllocationPopover({
     width: 300,
     estimatedHeight: 360,
     onClose,
+    ...(ignoreScrollContainers ? { ignoreScrollContainers } : {}),
   });
 
   const shouldLoadAllocation = !initialAllocation;
   const allocationQuery = trpc.allocation.getAssignmentById.useQuery(
     { id: allocationId },
     {
-      staleTime: 10_000,
+      staleTime: 0,
       enabled: shouldLoadAllocation,
       retry: false,
     },