feat: ST-101-ST-110 M1 producten, PBI backlog, iconen en PWA manifest

- Product aanmaken/bewerken/archiveren/herstellen (ST-101, ST-103)
- SplitPane component met versleepbare splitter en localStorage (ST-104)
- PanelNavBar herbruikbaar paneelheader component (ST-105)
- PbiList met prioriteitsgroepen, inline aanmaken, filter en verwijderen (ST-106-ST-110)
- StoryPanel placeholder rechter paneel met selectie via Zustand (ST-109)
- App iconen geinstalleerd: favicon, apple-icon, PWA manifest (192/512px)
- AppIcon SVG component in navigatiebar
- Root layout metadata bijgewerkt naar Nederlands

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

app/(app)/dashboard/page.tsx

@@ -6,24 +6,47 @@ import Link from 'next/link'
 import { Button } from '@/components/ui/button'
 import { ProductList } from '@/components/dashboard/product-list'
 
-export default async function DashboardPage() {
+interface Props {
+  searchParams: Promise<{ archived?: string }>
+}
+
+export default async function DashboardPage({ searchParams }: Props) {
   const session = await getIronSession<SessionData>(await cookies(), sessionOptions)
+  const { archived } = await searchParams
+  const showArchived = archived === '1'
 
   const products = await prisma.product.findMany({
-    where: { user_id: session.userId, archived: false },
+    where: { user_id: session.userId, archived: showArchived },
     orderBy: { created_at: 'desc' },
   })
 
   return (
     <div className="p-6 max-w-4xl mx-auto w-full">
       <div className="flex items-center justify-between mb-6">
-        <h1 className="text-xl font-medium text-foreground">Mijn Producten</h1>
-        {!session.isDemo && (
-          <Button render={<Link href="/products/new" />}>+ Nieuw product</Button>
+        <div className="flex items-center gap-3">
+          <h1 className="text-xl font-medium text-foreground">
+            {showArchived ? 'Gearchiveerde producten' : 'Mijn Producten'}
+          </h1>
+          {showArchived ? (
+            <Link href="/dashboard" className="text-xs text-primary hover:underline">
+              ← Actief
+            </Link>
+          ) : (
+            <Link href="/dashboard?archived=1" className="text-xs text-muted-foreground hover:text-foreground">
+              Toon gearchiveerd
+            </Link>
+          )}
+        </div>
+        {!session.isDemo && !showArchived && (
+          <Button nativeButton={false} render={<Link href="/products/new" />}>+ Nieuw product</Button>
         )}
       </div>
 
-      <ProductList products={products} isDemo={session.isDemo ?? false} />
+      <ProductList
+        products={products}
+        isDemo={session.isDemo ?? false}
+        showArchived={showArchived}
+      />
     </div>
   )
 }