refactor(application): extract vacation management into application use-cases

Moves approve, reject, cancel, and request vacation business logic
out of the tRPC procedure layer into packages/application, matching
the pattern used by allocation use-cases.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/application/src/use-cases/vacation/reject-vacation.ts

@@ -0,0 +1,79 @@
+import type { Prisma, PrismaClient, VacationStatus } from "@capakraken/db";
+import { TRPCError } from "@trpc/server";
+
+type DbClient = Pick<PrismaClient, "vacation">;
+
+export type RejectVacationDeps = {
+  assertVacationRejectable: (status: VacationStatus) => void;
+  buildRejectedVacationUpdateData: (input: {
+    rejectionReason?: string | undefined;
+  }) => Prisma.VacationUncheckedUpdateInput;
+};
+
+export type RejectVacationInput = {
+  id: string;
+  rejectionReason?: string | undefined;
+};
+
+export type RejectVacationResult = {
+  vacation: Awaited<ReturnType<PrismaClient["vacation"]["update"]>>;
+};
+
+export async function rejectVacation(
+  db: DbClient,
+  input: RejectVacationInput,
+  deps: RejectVacationDeps,
+): Promise<RejectVacationResult> {
+  const existing = await db.vacation.findUnique({ where: { id: input.id } });
+  if (!existing) {
+    throw new TRPCError({ code: "NOT_FOUND", message: "Vacation not found" });
+  }
+
+  deps.assertVacationRejectable(existing.status);
+
+  const updated = await db.vacation.update({
+    where: { id: input.id },
+    data: deps.buildRejectedVacationUpdateData({
+      rejectionReason: input.rejectionReason,
+    }),
+  });
+
+  return { vacation: updated };
+}
+
+export type BatchRejectVacationDeps = {
+  buildRejectedVacationUpdateData: (input: {
+    rejectionReason?: string | undefined;
+  }) => Prisma.VacationUncheckedUpdateInput;
+};
+
+export type BatchRejectVacationInput = {
+  ids: string[];
+  rejectionReason?: string | undefined;
+};
+
+export type BatchRejectVacationResult = {
+  rejected: number;
+  vacations: Array<{ id: string; resourceId: string }>;
+};
+
+export async function batchRejectVacations(
+  db: DbClient,
+  input: BatchRejectVacationInput,
+  deps: BatchRejectVacationDeps,
+): Promise<BatchRejectVacationResult> {
+  const vacations: Array<{ id: string; resourceId: string }> =
+    await db.vacation.findMany({
+      where: { id: { in: input.ids }, status: "PENDING" },
+      select: { id: true, resourceId: true },
+    });
+
+  await db.vacation.updateMany({
+    where: { id: { in: vacations.map((v) => v.id) } },
+    data: deps.buildRejectedVacationUpdateData({
+      rejectionReason: input.rejectionReason,
+    }),
+  });
+
+  return { rejected: vacations.length, vacations };
+}