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>

packages/api/src/router/staffing-capacity-read.ts

@@ -1,5 +1,5 @@
 import { listAssignmentBookings } from "@capakraken/application";
-import { type WeekdayAvailability } from "@capakraken/shared";
+import { MILLISECONDS_PER_DAY, type WeekdayAvailability } from "@capakraken/shared";
 import { z } from "zod";
 import { findUniqueOrThrow } from "../db/helpers.js";
 import {
@@ -378,7 +378,7 @@ export const staffingCapacityReadProcedures = {
         cursor.setUTCDate(cursor.getUTCDate() + 1);
       }
 
-      closeWindow(new Date(end.getTime() + 86_400_000));
+      closeWindow(new Date(end.getTime() + MILLISECONDS_PER_DAY));
 
       return windows;
     }),