feat(frontend): PageHeader auf den restlichen Hauptseiten

Inventar, Produkte, Lager, Kalender, Suche und Audit-Log bekommen den
gleichen Gradient-Icon-Header wie die uebrigen Seiten. Lager-Seite hatte
zwei h1-artige Ueberschriften fuer zwei Abschnitte (Lagerbehaelter/
Lagerartikel) auf einer Seite; jetzt ein PageHeader fuer die Seite plus
gleich grosse Unterueberschriften fuer beide Abschnitte statt
uneinheitlicher Groessen.

ApiCore-Frontend/src/app/(app)/calendar/page.tsx

@@ -4,6 +4,7 @@ import { useMemo, useState } from "react";
 import Link from "next/link";
 import { useQuery } from "@tanstack/react-query";
 import {
+  CalendarDays,
   ChevronLeft,
   ChevronRight,
   ClipboardCheck,
@@ -18,6 +19,7 @@ import { fetchCalendarEvents } from "@/lib/calendar/api";
 import { CalendarEvent, CalendarEventType } from "@/lib/calendar/types";
 import { fetchApiaries } from "@/lib/apiaries/api";
 import { Button } from "@/components/ui/button";
+import { PageHeader } from "@/components/page-header";
 import {
   Select,
   SelectContent,
@@ -108,10 +110,12 @@ export default function CalendarPage() {
 
   return (
     <main className="flex flex-col gap-4 p-4 sm:p-6">
-      <div className="flex flex-wrap items-center justify-between gap-3">
-        <h1 className="text-2xl font-semibold tracking-tight">
-          {month.toLocaleDateString("de-DE", { month: "long", year: "numeric" })}
-        </h1>
+      <PageHeader
+        icon={CalendarDays}
+        title={month.toLocaleDateString("de-DE", { month: "long", year: "numeric" })}
+        description="Kalender"
+        gradient="var(--gradient-sky)"
+        actions={
           <div className="flex items-center gap-2">
           <Select
             value={apiaryId || "ALL"}
@@ -150,7 +154,8 @@ export default function CalendarPage() {
             <ChevronRight className="size-4" />
           </Button>
           </div>
-      </div>
+        }
+      />
 
       {isLoading ? <p className="text-sm text-muted-foreground">Lädt…</p> : null}
       {isError ? (

ApiCore-Frontend/src/app/(app)/equipment/page.tsx

@@ -1,11 +1,13 @@
 "use client";
 
 import Link from "next/link";
+import { Wrench } from "lucide-react";
 import { useQuery } from "@tanstack/react-query";
 import { fetchEquipmentList } from "@/lib/equipment/api";
 import { statusTone } from "@/lib/status-tone";
 import { Badge } from "@/components/ui/badge";
 import { Button } from "@/components/ui/button";
+import { PageHeader } from "@/components/page-header";
 import {
   Table,
   TableBody,
@@ -23,12 +25,17 @@ export default function EquipmentPage() {
 
   return (
     <main className="flex flex-col gap-4 p-4 sm:p-6">
-      <div className="flex items-center justify-between">
-        <h1 className="text-2xl font-semibold tracking-tight">Inventar</h1>
+      <PageHeader
+        icon={Wrench}
+        title="Inventar"
+        description="Ausrüstung und Zustand im Blick"
+        gradient="var(--gradient-sage)"
+        actions={
           <Button nativeButton={false} render={<Link href="/equipment/new" />}>
             + Neuer Gegenstand
           </Button>
-      </div>
+        }
+      />
 
       {isLoading ? <p className="text-sm text-muted-foreground">Lädt…</p> : null}
       {isError ? (

ApiCore-Frontend/src/app/(app)/products/page.tsx

@@ -1,10 +1,12 @@
 "use client";
 
 import Link from "next/link";
+import { ShoppingBag } from "lucide-react";
 import { useQuery } from "@tanstack/react-query";
 import { fetchProducts } from "@/lib/products/api";
 import { Badge } from "@/components/ui/badge";
 import { Button } from "@/components/ui/button";
+import { PageHeader } from "@/components/page-header";
 import {
   Table,
   TableBody,
@@ -22,12 +24,16 @@ export default function ProductsPage() {
 
   return (
     <main className="flex flex-col gap-4 p-4 sm:p-6">
-      <div className="flex items-center justify-between">
-        <h1 className="text-2xl font-semibold tracking-tight">Produkte</h1>
+      <PageHeader
+        icon={ShoppingBag}
+        title="Produkte"
+        description="Verkaufsfertige Produkte"
+        actions={
           <Button nativeButton={false} render={<Link href="/products/new" />}>
             + Neues Produkt
           </Button>
-      </div>
+        }
+      />
 
       {isLoading ? <p className="text-sm text-muted-foreground">Lädt…</p> : null}
       {isError ? (

ApiCore-Frontend/src/app/(app)/search/page.tsx

@@ -2,11 +2,13 @@
 
 import { useState } from "react";
 import Link from "next/link";
+import { Search as SearchIcon } from "lucide-react";
 import { useQuery } from "@tanstack/react-query";
 import { search } from "@/lib/search/api";
 import { SearchResult, SearchResultType } from "@/lib/search/types";
 import { Badge } from "@/components/ui/badge";
 import { Input } from "@/components/ui/input";
+import { PageHeader } from "@/components/page-header";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 
 const TYPE_LABELS: Record<SearchResultType, string> = {
@@ -43,7 +45,7 @@ export default function SearchPage() {
 
   return (
     <main className="flex flex-col gap-4 p-4 sm:p-6">
-      <h1 className="text-2xl font-semibold tracking-tight">Suche</h1>
+      <PageHeader icon={SearchIcon} title="Suche" description="Alles auf einen Blick finden" />
       <Input
         className="h-11 max-w-lg"
         placeholder="Bienenstand, Volk, Königin, Aufgabe, Charge…"

ApiCore-Frontend/src/app/(app)/settings/audit-log/page.tsx

@@ -1,10 +1,12 @@
 "use client";
 
 import { useState } from "react";
+import { History } from "lucide-react";
 import { useQuery } from "@tanstack/react-query";
 import { fetchAuditLog } from "@/lib/audit-log/api";
 import { Input } from "@/components/ui/input";
 import { Button } from "@/components/ui/button";
+import { PageHeader } from "@/components/page-header";
 import {
   Table,
   TableBody,
@@ -30,7 +32,7 @@ export default function AuditLogPage() {
 
   return (
     <main className="flex flex-col gap-4 p-4 sm:p-6">
-      <h1 className="text-2xl font-semibold tracking-tight">Audit-Log</h1>
+      <PageHeader icon={History} title="Audit-Log" description="Nachvollziehbare Änderungen" gradient="var(--gradient-sage)" />
 
       <form
         className="flex flex-wrap items-end gap-3"

ApiCore-Frontend/src/app/(app)/storage/page.tsx

@@ -1,8 +1,10 @@
 "use client";
 
+import { Warehouse } from "lucide-react";
 import { useQuery } from "@tanstack/react-query";
 import { fetchStockItems, fetchStorageContainers } from "@/lib/storage/api";
 import { QrCodeDialog } from "@/components/qr-code-dialog";
+import { PageHeader } from "@/components/page-header";
 import { Badge } from "@/components/ui/badge";
 import {
   Table,
@@ -29,10 +31,14 @@ export default function StoragePage() {
   return (
     <main className="flex flex-col gap-8 p-4 sm:p-6">
       <section className="flex flex-col gap-4">
-        <div className="flex items-center justify-between">
-          <h1 className="text-2xl font-semibold tracking-tight">Lagerbehälter</h1>
-          <CreateStorageContainerDialog />
-        </div>
+        <PageHeader
+          icon={Warehouse}
+          title="Lager"
+          description="Lagerbehälter und Lagerartikel"
+          gradient="var(--gradient-sky)"
+          actions={<CreateStorageContainerDialog />}
+        />
+        <h2 className="text-lg font-semibold tracking-tight">Lagerbehälter</h2>
         {containersLoading ? <p className="text-sm text-muted-foreground">Lädt…</p> : null}
         {containers ? (
           <Table>
@@ -68,7 +74,7 @@ export default function StoragePage() {
 
       <section className="flex flex-col gap-4">
         <div className="flex items-center justify-between">
-          <h2 className="text-2xl font-semibold tracking-tight">Lagerartikel</h2>
+          <h2 className="text-lg font-semibold tracking-tight">Lagerartikel</h2>
           <CreateStockItemDialog />
         </div>
         {itemsLoading ? <p className="text-sm text-muted-foreground">Lädt…</p> : null}