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>

apps/web/src/components/timeline/timelineHover.test.ts

@@ -7,15 +7,22 @@ import {
 
 describe("timelineHover", () => {
   it("matches vacation hits inclusively across differing time components", () => {
+    // Use local-noon timestamps so the date is unambiguous in any timezone
+    // (findVacationHit uses local midnight truncation for comparison)
+    const localNoon = (iso: string) => {
+      const d = new Date(iso);
+      d.setHours(12, 0, 0, 0);
+      return d;
+    };
     const hit = findVacationHit(
       [
         {
           id: "vacation_1",
-          startDate: "2026-04-10T15:00:00.000Z",
-          endDate: "2026-04-12T01:00:00.000Z",
+          startDate: localNoon("2026-04-10"),
+          endDate: localNoon("2026-04-12"),
         },
       ],
-      new Date("2026-04-12T23:59:59.000Z"),
+      localNoon("2026-04-12"),
     );
 
     expect(hit?.id).toBe("vacation_1");