feat(ST-1136): mobile Settings-pagina + LogoutButton (T-325/T-326/T-327)

- app/(mobile)/m/settings/page.tsx — read-only account-info, product-selector
  (hergebruikt ActivateProductButton + setActiveProductAction met redirectTo
  /m/products/[id]/solo), QR-pairing-instructie, logout
- components/mobile/logout-button.tsx — AlertDialog "Uitloggen?" met bevestig
  + annuleer; demo-user mag uitloggen (geen demo-block)
- Tests: LogoutButton render + open + bevestig (logoutAction) + annuleer

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/(mobile)/m/settings/page.tsx

@@ -0,0 +1,92 @@
+// PBI-11 / ST-1136: Mobile Settings — read-only account, product-selector,
+// QR-pairing-instructie, logout. Eigenlijke productactivering loopt via de
+// bestaande setActiveProductAction (ActivateProductButton).
+
+import Link from 'next/link'
+import { prisma } from '@/lib/prisma'
+import { productAccessFilter } from '@/lib/product-access'
+import { requireSession } from '@/lib/auth-guard'
+import { ActivateProductButton } from '@/components/shared/activate-product-button'
+import { LogoutButton } from '@/components/mobile/logout-button'
+import { Badge } from '@/components/ui/badge'
+
+export const metadata = {
+  title: 'Settings',
+}
+
+export default async function MobileSettingsPage() {
+  const session = await requireSession()
+
+  const [user, products] = await Promise.all([
+    prisma.user.findUnique({
+      where: { id: session.userId },
+      select: { username: true, is_demo: true, active_product_id: true },
+    }),
+    prisma.product.findMany({
+      where: { archived: false, ...productAccessFilter(session.userId) },
+      orderBy: { name: 'asc' },
+      select: { id: true, name: true },
+    }),
+  ])
+
+  const isDemo = user?.is_demo ?? false
+
+  return (
+    <div className="px-4 py-6 space-y-6 max-w-md mx-auto w-full">
+      <h1 className="text-xl font-semibold">Settings</h1>
+
+      <section aria-labelledby="account-heading" className="space-y-2">
+        <h2 id="account-heading" className="text-sm font-medium text-muted-foreground uppercase tracking-wide">Account</h2>
+        <div className="flex items-center gap-2">
+          <span className="text-base font-medium">{user?.username ?? '—'}</span>
+          {isDemo && (
+            <Badge className="bg-status-todo/15 text-status-todo border-status-todo/30">Demo</Badge>
+          )}
+        </div>
+      </section>
+
+      <section aria-labelledby="product-heading" className="space-y-2">
+        <h2 id="product-heading" className="text-sm font-medium text-muted-foreground uppercase tracking-wide">Actief product</h2>
+        {products.length === 0 ? (
+          <p className="text-sm text-muted-foreground">Geen producten beschikbaar.</p>
+        ) : (
+          <ul className="divide-y divide-border rounded border border-border">
+            {products.map((p) => {
+              const active = p.id === user?.active_product_id
+              return (
+                <li key={p.id} className="flex items-center justify-between px-3 py-3">
+                  <div className="flex items-center gap-2 min-w-0">
+                    <span className="text-sm truncate">{p.name}</span>
+                    {active && (
+                      <Badge className="bg-primary/15 text-primary border-primary/30">Actief</Badge>
+                    )}
+                  </div>
+                  {!active && (
+                    <ActivateProductButton
+                      productId={p.id}
+                      isDemo={isDemo}
+                      redirectTo={`/m/products/${p.id}/solo`}
+                      label="Activeer"
+                    />
+                  )}
+                </li>
+              )
+            })}
+          </ul>
+        )}
+      </section>
+
+      <section aria-labelledby="qr-heading" className="space-y-2">
+        <h2 id="qr-heading" className="text-sm font-medium text-muted-foreground uppercase tracking-wide">Inloggen op desktop</h2>
+        <p className="text-sm text-muted-foreground">
+          Open <Link href="/login" className="text-primary hover:underline">scrum4me.app/login</Link> op je desktop om in te loggen via QR-code. QR-pairing start vanaf de desktop.
+        </p>
+      </section>
+
+      <section aria-labelledby="logout-heading" className="space-y-2 pt-2">
+        <h2 id="logout-heading" className="sr-only">Uitloggen</h2>
+        <LogoutButton />
+      </section>
+    </div>
+  )
+}