Initial commit: Fahrrad Verschleißteile Tracker

- Next.js SPA mit Bun Runtime
- Prisma mit SQLite Datenbank
- Vollständige CRUD-Operationen für Fahrräder, Verschleißteile und Wartungshistorie
- Warnsystem für bevorstehende Wartungen
- Statistik-Features (Gesamtkosten, durchschnittliche Lebensdauer)
- Zod-Validierung für alle API-Requests
- Umfassende Test-Suite (41 Tests)

app/page.tsx

@@ -0,0 +1,92 @@
+'use client'
+
+import { useEffect, useState } from 'react'
+import { BikeWithParts } from '@/types'
+import BikeCard from '@/app/components/BikeCard'
+import BikeForm from '@/app/components/BikeForm'
+import StatsCard from '@/app/components/StatsCard'
+
+export default function Home() {
+  const [bikes, setBikes] = useState<BikeWithParts[]>([])
+  const [loading, setLoading] = useState(true)
+  const [showForm, setShowForm] = useState(false)
+
+  useEffect(() => {
+    fetchBikes()
+  }, [])
+
+  const fetchBikes = async () => {
+    try {
+      const response = await fetch('/api/bikes')
+      if (response.ok) {
+        const data = await response.json()
+        setBikes(data)
+      }
+    } catch (error) {
+      console.error('Error fetching bikes:', error)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  const handleBikeCreated = () => {
+    setShowForm(false)
+    fetchBikes()
+  }
+
+  const handleBikeDeleted = () => {
+    fetchBikes()
+  }
+
+  if (loading) {
+    return (
+      <div className="min-h-screen flex items-center justify-center">
+        <div className="text-lg">Lade...</div>
+      </div>
+    )
+  }
+
+  return (
+    <main className="min-h-screen p-8 bg-gray-50">
+      <div className="max-w-7xl mx-auto">
+        <div className="mb-8 flex justify-between items-center">
+          <h1 className="text-4xl font-bold text-gray-900">
+            Fahrrad Verschleißteile Tracker
+          </h1>
+          <button
+            onClick={() => setShowForm(!showForm)}
+            className="px-6 py-3 bg-blue-600 text-white rounded-lg hover:bg-blue-700 transition-colors"
+          >
+            {showForm ? 'Abbrechen' : '+ Neues Fahrrad'}
+          </button>
+        </div>
+
+        {showForm && (
+          <div className="mb-8">
+            <BikeForm onSuccess={handleBikeCreated} onCancel={() => setShowForm(false)} />
+          </div>
+        )}
+
+        <StatsCard bikes={bikes} />
+
+        <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6 mt-8">
+          {bikes.length === 0 ? (
+            <div className="col-span-full text-center py-12 text-gray-500">
+              <p className="text-lg">Noch keine Fahrräder erfasst.</p>
+              <p className="mt-2">Klicken Sie auf &quot;Neues Fahrrad&quot; um zu beginnen.</p>
+            </div>
+          ) : (
+            bikes.map((bike) => (
+              <BikeCard
+                key={bike.id}
+                bike={bike}
+                onDelete={handleBikeDeleted}
+              />
+            ))
+          )}
+        </div>
+      </div>
+    </main>
+  )
+}
+