fix: resend offline-queued entries with an idempotency key

When the server saved an inspection, harvest, treatment, feeding, varroa
measurement or swarm check but the answer was lost (dead zone at the
apiary), the form queued the entry and the sync later created it a second
time - including a second automation task. Each opened form now creates
one Idempotency-Key, sends it with the request and stores it with the
queued entry, so the retry returns the first record. Entries queued before
this change still sync without a key.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

ApiCore-Frontend/src/lib/harvests/api.ts

@@ -1,4 +1,5 @@
 import { apiFetch } from "@/lib/auth/api-client";
+import { CreateOptions, idempotencyHeaders } from "@/lib/offline/idempotency";
 import { CreateHarvestInput, Harvest, UpdateHarvestInput } from "./types";
 
 export function fetchHarvests(): Promise<Harvest[]> {
@@ -9,9 +10,13 @@ export function fetchHarvest(id: string): Promise<Harvest> {
   return apiFetch<Harvest>(`/harvests/${id}`);
 }
 
-export function createHarvest(input: CreateHarvestInput): Promise<Harvest> {
+export function createHarvest(
+  input: CreateHarvestInput,
+  options: CreateOptions = {},
+): Promise<Harvest> {
   return apiFetch<Harvest>("/harvests", {
     method: "POST",
+    headers: idempotencyHeaders(options),
     body: JSON.stringify(input),
   });
 }