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/resource-capacity-shared.ts

@@ -1,4 +1,5 @@
-import type { WeekdayAvailability } from "@capakraken/shared";
+import { toIsoDate, type WeekdayAvailability } from "@capakraken/shared";
+export { toIsoDate } from "@capakraken/shared";
 import { calculateEffectiveBookedHours } from "../lib/resource-capacity.js";
 
 type BookingForCapacity = {
@@ -7,10 +8,6 @@ type BookingForCapacity = {
   hoursPerDay: number;
 };
 
-export function toIsoDate(value: Date): string {
-  return value.toISOString().slice(0, 10);
-}
-
 export function buildDailyBookedHoursMap(
   bookings: BookingForCapacity[],
   availability: WeekdayAvailability,