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-shared.ts

@@ -1,22 +1,9 @@
-import { type WeekdayAvailability } from "@capakraken/shared";
-import { type ResourceDailyAvailabilityContext } from "../lib/resource-capacity.js";
-
-const DAY_KEYS: (keyof WeekdayAvailability)[] = [
-  "sunday",
-  "monday",
-  "tuesday",
-  "wednesday",
-  "thursday",
-  "friday",
-  "saturday",
-];
+import { toIsoDate, type WeekdayAvailability } from "@capakraken/shared";
+export { toIsoDate, round1, averagePerWorkingDay } from "@capakraken/shared";
+import { getAvailabilityHoursForDate, calculateEffectiveDayAvailability as _calcEffective, type ResourceDailyAvailabilityContext } from "../lib/resource-capacity.js";
 
 export const ACTIVE_STATUSES = new Set(["PROPOSED", "CONFIRMED", "ACTIVE"]);
 
-export function toIsoDate(value: Date): string {
-  return value.toISOString().slice(0, 10);
-}
-
 function createUtcDate(year: number, monthIndex: number, day: number): Date {
   return new Date(Date.UTC(year, monthIndex, day));
 }
@@ -48,16 +35,11 @@ export function createDateRange(input: {
   return { startDate, endDate };
 }
 
-export function round1(value: number): number {
-  return Math.round(value * 10) / 10;
-}
-
 export function getBaseDayAvailability(
   availability: WeekdayAvailability,
   date: Date,
 ): number {
-  const key = DAY_KEYS[date.getUTCDay()];
-  return key ? (availability[key] ?? 0) : 0;
+  return getAvailabilityHoursForDate(availability, date);
 }
 
 export function getEffectiveDayAvailability(
@@ -65,25 +47,13 @@ export function getEffectiveDayAvailability(
   date: Date,
   context: ResourceDailyAvailabilityContext | undefined,
 ): number {
-  const key = DAY_KEYS[date.getUTCDay()];
-  const baseHours = key ? (availability[key] ?? 0) : 0;
-  if (baseHours <= 0) {
-    return 0;
-  }
-  const fraction = context?.absenceFractionsByDate.get(toIsoDate(date)) ?? 0;
-  return Math.max(0, baseHours * (1 - fraction));
+  return _calcEffective({ availability, date, context });
 }
 
 function overlapsDateRange(startDate: Date, endDate: Date, date: Date): boolean {
   return date >= startDate && date <= endDate;
 }
 
-export function averagePerWorkingDay(totalHours: number, workingDays: number): number {
-  if (workingDays <= 0) {
-    return 0;
-  }
-  return round1(totalHours / workingDays);
-}
 
 export function createLocationLabel(input: {
   countryCode?: string | null;