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/engine/src/allocation/chargeability.ts

@@ -1,4 +1,4 @@
-import type { WeekdayAvailability } from "@capakraken/shared";
+import { DAY_KEYS, type WeekdayAvailability } from "@capakraken/shared";
 
 export interface ChargeabilityAllocation {
   startDate: Date;
@@ -12,11 +12,6 @@ export interface ChargeabilityResult {
   chargeability: number; // 0-100, rounded
 }
 
-// Maps JS getDay() (0=Sun..6=Sat) to WeekdayAvailability keys
-const DAY_KEYS: (keyof WeekdayAvailability)[] = [
-  "sunday", "monday", "tuesday", "wednesday", "thursday", "friday", "saturday",
-];
-
 /** Count working hours a resource has available in [start, end] based on their schedule. */
 export function computeAvailableHours(
   availability: WeekdayAvailability,