feat(frontend): Ernten- und Schleuderungs-Ansichten (Modul 10)

/harvests/new (Bienenstand + Mehrfachauswahl Völker), /harvests/[id]
und /extractions/new (Mehrfachauswahl Ernten). Bienenstand- und
Ernte-Detailseiten verlinken direkt in die Kette.

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

@@ -0,0 +1,13 @@
+import { apiFetch } from "@/lib/auth/api-client";
+import { CreateExtractionInput, Extraction } from "./types";
+
+export function fetchExtractions(): Promise<Extraction[]> {
+  return apiFetch<Extraction[]>("/extractions");
+}
+
+export function createExtraction(input: CreateExtractionInput): Promise<Extraction> {
+  return apiFetch<Extraction>("/extractions", {
+    method: "POST",
+    body: JSON.stringify(input),
+  });
+}

ApiCore-Frontend/src/lib/extractions/types.ts

@@ -0,0 +1,35 @@
+export interface ExtractionHarvestEntry {
+  id: string;
+  harvestId: string;
+  harvest: {
+    id: string;
+    date: string;
+    colonies: {
+      colonyId: string;
+      colony: { id: string; code: string };
+    }[];
+  };
+}
+
+export interface Extraction {
+  id: string;
+  date: string;
+  userId: string;
+  amount: number | null;
+  room: string | null;
+  waterContent: number | null;
+  temperature: number | null;
+  notes: string | null;
+  createdAt: string;
+  harvests: ExtractionHarvestEntry[];
+}
+
+export interface CreateExtractionInput {
+  date: string;
+  harvestIds: string[];
+  amount?: number;
+  room?: string;
+  waterContent?: number;
+  temperature?: number;
+  notes?: string;
+}