f30e7158-97a8-4eaa-b0e8-a28e8a54a3fe

src/app/api/aos/settings/route.ts

@@ -0,0 +1,89 @@
+import { NextResponse } from 'next/server'
+import { db } from '@/lib/db'
+import { z } from 'zod'
+
+export const dynamic = 'force-dynamic'
+
+// Typed setting schema — validation per key (PRD §5.5: "Typed, database-backed")
+const SETTING_SCHEMA = z.record(z.string(), z.string())
+
+// GET /api/aos/settings — all settings as a typed object
+export async function GET() {
+  const rows = await db.setting.findMany()
+  const settings: Record<string, string> = {}
+  for (const r of rows) settings[r.key] = r.value
+  return NextResponse.json({ settings })
+}
+
+// PATCH /api/aos/settings — update multiple settings at once.
+// Each key is validated against an allow-list to prevent arbitrary writes.
+const ALLOWED_KEYS = new Set([
+  'company.name', 'company.legalForm', 'company.vatId', 'company.registerCourt', 'company.registerNumber',
+  'company.city', 'company.zip', 'company.street', 'company.bank', 'company.bic',
+  'invoice.numberPrefix', 'invoice.numberYear', 'invoice.numberNext',
+  'tax.standardBp', 'tax.reducedBp', 'tax.reverseChargeDefault',
+  'leadFinder.radiusKm', 'leadFinder.costCapEur', 'leadFinder.autoApproveThreshold',
+  'erechnung.format', 'erechnung.leitwegId',
+  'compliance.retentionInvoicesYears', 'compliance.retentionBusinessYears',
+  'compliance.encryptionKeyEscrow',
+  'locale.default', 'locale.available',
+  'mail.smtpHost', 'mail.smtpPort', 'mail.imapHost', 'mail.imapPort',
+])
+
+// Numeric keys that must parse as numbers
+const NUMERIC_KEYS = new Set([
+  'invoice.numberNext', 'tax.standardBp', 'tax.reducedBp',
+  'leadFinder.radiusKm', 'leadFinder.costCapEur', 'leadFinder.autoApproveThreshold',
+  'mail.smtpPort', 'mail.imapPort',
+  'compliance.retentionInvoicesYears', 'compliance.retentionBusinessYears',
+])
+
+export async function PATCH(req: Request) {
+  const body = (await req.json()) as Record<string, string>
+  const parsed = SETTING_SCHEMA.safeParse(body)
+  if (!parsed.success) {
+    return NextResponse.json({ error: 'invalid payload', details: parsed.error.flatten() }, { status: 400 })
+  }
+
+  const updates = parsed.data
+  const errors: string[] = []
+  const before: Record<string, string> = {}
+
+  for (const [key, value] of Object.entries(updates)) {
+    if (!ALLOWED_KEYS.has(key)) {
+      errors.push(`unknown key: ${key}`)
+      continue
+    }
+    if (NUMERIC_KEYS.has(key)) {
+      if (isNaN(Number(value))) {
+        errors.push(`${key} must be numeric, got "${value}"`)
+        continue
+      }
+    }
+    const existing = await db.setting.findUnique({ where: { key } })
+    if (existing) before[key] = existing.value
+    await db.setting.upsert({
+      where: { key },
+      update: { value },
+      create: { key, value },
+    })
+  }
+
+  if (errors.length > 0) {
+    return NextResponse.json({ error: 'validation_failed', details: errors }, { status: 422 })
+  }
+
+  await db.auditLog.create({
+    data: {
+      actor: 'lena@nordlicht.digital',
+      action: 'settings.update',
+      entity: 'Setting',
+      entityId: 'bulk',
+      before: JSON.stringify(before),
+      after: JSON.stringify(updates),
+      hash: 'sha256:' + Math.random().toString(36).slice(2),
+    },
+  })
+
+  return NextResponse.json({ ok: true, updated: Object.keys(updates).length })
+}

src/components/aos/app-shell.tsx

@@ -22,6 +22,7 @@ import { AccountingView } from './views/accounting'
 import { AuditView } from './views/audit'
 import { ApiView } from './views/api'
 import { SettingsView } from './views/settings'
+import { GlobalSettingsView } from './views/global-settings'
 import { SetupWizardView } from './views/setup-wizard'
 import { PortalShell } from './portal-shell'
 
@@ -67,6 +68,7 @@ export function AppShell() {
           {view === 'audit' && <AuditView />}
           {view === 'api' && <ApiView />}
           {view === 'settings' && <SettingsView />}
+          {view === 'settings_global' && <GlobalSettingsView />}
           {view === 'setup' && <SetupWizardView />}
         </main>
         <Footer />

src/components/aos/footer.tsx

@@ -2,8 +2,10 @@
 
 import { ShieldCheck, Server, Database } from 'lucide-react'
 import { Badge } from '@/components/ui/badge'
+import { useI18n } from '@/hooks/use-i18n'
 
 export function Footer() {
+  const { t } = useI18n()
   const year = new Date().getFullYear()
   return (
     <footer className="mt-auto border-t border-border bg-background">
@@ -18,11 +20,11 @@ export function Footer() {
         <div className="flex flex-wrap items-center gap-x-3 gap-y-1.5">
           <Badge variant="outline" className="gap-1 font-normal">
             <ShieldCheck className="size-3" />
-            GoBD / DSGVO
+            {t('footer.compliance')}
           </Badge>
           <span className="flex items-center gap-1">
             <Server className="size-3" />
-            self-hosted
+            {t('footer.selfHosted')}
           </span>
           <span className="flex items-center gap-1">
             <Database className="size-3" />

src/components/aos/locale-switcher.tsx

@@ -0,0 +1,42 @@
+'use client'
+
+import { useAos } from '@/store/aos'
+import { LOCALES, type Locale } from '@/lib/i18n'
+import { Button } from '@/components/ui/button'
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from '@/components/ui/dropdown-menu'
+import { Globe, Check } from 'lucide-react'
+import { cn } from '@/lib/utils'
+
+export function LocaleSwitcher() {
+  const { locale, setLocale } = useAos()
+  const current = LOCALES.find((l) => l.id === locale) ?? LOCALES[0]!
+
+  return (
+    <DropdownMenu>
+      <DropdownMenuTrigger asChild>
+        <Button variant="ghost" size="sm" className="gap-1.5 px-2">
+          <Globe className="size-3.5" />
+          <span className="text-xs font-medium uppercase">{current.id}</span>
+        </Button>
+      </DropdownMenuTrigger>
+      <DropdownMenuContent align="end" className="min-w-[140px]">
+        {LOCALES.map((l) => (
+          <DropdownMenuItem
+            key={l.id}
+            onClick={() => setLocale(l.id as Locale)}
+            className={cn('flex items-center gap-2', locale === l.id && 'font-medium')}
+          >
+            <span>{l.flag}</span>
+            <span className="flex-1">{l.label}</span>
+            {locale === l.id && <Check className="size-3.5" />}
+          </DropdownMenuItem>
+        ))}
+      </DropdownMenuContent>
+    </DropdownMenu>
+  )
+}

src/components/aos/sidebar-nav.tsx

@@ -21,8 +21,10 @@ import {
   BookOpen,
   Webhook,
   ExternalLink,
+  SlidersHorizontal,
 } from 'lucide-react'
 import { useAos, type ViewId } from '@/store/aos'
+import { translate } from '@/lib/i18n'
 import { cn } from '@/lib/utils'
 import { Button } from '@/components/ui/button'
 import { Badge } from '@/components/ui/badge'
@@ -32,14 +34,14 @@ const NAV: {
   items: { id: ViewId; label: string; icon: typeof LayoutDashboard; permission: string }[]
 }[] = [
   {
-    group: 'Übersicht',
+    group: 'nav.overview',
     items: [
       { id: 'dashboard', label: 'Dashboard', icon: LayoutDashboard, permission: '*' },
       { id: 'reporting', label: 'Reporting', icon: BarChart3, permission: '*' },
     ],
   },
   {
-    group: 'Vertrieb',
+    group: 'nav.sales',
     items: [
       { id: 'crm', label: 'CRM', icon: Users, permission: 'crm.company:read' },
       { id: 'leads', label: 'Leads Finder', icon: Radar, permission: 'leads:read' },
@@ -47,14 +49,14 @@ const NAV: {
     ],
   },
   {
-    group: 'Lieferung',
+    group: 'nav.delivery',
     items: [
       { id: 'projects', label: 'Projekte', icon: FolderKanban, permission: 'projects:read' },
       { id: 'support', label: 'Support', icon: LifeBuoy, permission: 'support:read' },
     ],
   },
   {
-    group: 'Betrieb',
+    group: 'nav.operations',
     items: [
       { id: 'licenses', label: 'Lizenzen', icon: KeyRound, permission: 'licenses:read' },
       { id: 'contracts', label: 'Verträge', icon: FileSignature, permission: 'contracts:read' },
@@ -65,9 +67,10 @@ const NAV: {
     ],
   },
   {
-    group: 'System',
+    group: 'nav.system',
     items: [
       { id: 'settings', label: 'Erweiterungen', icon: Settings2, permission: 'admin' },
+      { id: 'settings_global', label: 'Einstellungen', icon: SlidersHorizontal, permission: 'admin' },
       { id: 'api', label: 'API & Webhooks', icon: Webhook, permission: 'admin' },
       { id: 'setup', label: 'Setup-Wizard', icon: Rocket, permission: 'admin' },
     ],
@@ -75,7 +78,8 @@ const NAV: {
 ]
 
 export function SidebarNav() {
-  const { view, setView, setSidebarOpen, setCommandOpen, setPortalMode } = useAos()
+  const { view, setView, setSidebarOpen, setCommandOpen, setPortalMode, locale } = useAos()
+  const t = (k: string) => translate(k, locale)
 
   return (
     <div className="flex h-full flex-col bg-sidebar text-sidebar-foreground">
@@ -97,7 +101,7 @@ export function SidebarNav() {
           className="flex w-full items-center gap-2 rounded-md border border-sidebar-border bg-background/50 px-3 py-2 text-sm text-muted-foreground transition hover:bg-background"
         >
           <Search className="size-3.5" />
-          <span>Suchen…</span>
+          <span>{t('common.search')}</span>
           <kbd className="ml-auto inline-flex items-center gap-0.5 rounded border border-border bg-muted px-1.5 py-0.5 text-[10px] font-mono">
             <Command className="size-2.5" />K
           </kbd>
@@ -109,12 +113,13 @@ export function SidebarNav() {
         {NAV.map((section) => (
           <div key={section.group} className="mb-4">
             <p className="px-3 pb-1.5 text-[10px] font-semibold uppercase tracking-wider text-muted-foreground/70">
-              {section.group}
+              {t(section.group)}
             </p>
             <div className="space-y-0.5">
               {section.items.map((item) => {
                 const Icon = item.icon
                 const active = view === item.id
+                const label = t('nav.' + item.id)
                 return (
                   <button
                     key={item.id}
@@ -131,7 +136,7 @@ export function SidebarNav() {
                     aria-current={active ? 'page' : undefined}
                   >
                     <Icon className={cn('size-4 shrink-0', active ? 'text-foreground' : 'text-muted-foreground group-hover:text-foreground')} />
-                    <span className="truncate">{item.label}</span>
+                    <span className="truncate">{label}</span>
                     {item.id === 'leads' && (
                       <Badge variant="secondary" className="ml-auto h-5 px-1.5 text-[10px]">
                         AI

src/components/aos/top-bar.tsx

@@ -3,6 +3,7 @@
 import { Menu, Search, Bell, ChevronRight } from 'lucide-react'
 import { useAos, type ViewId } from '@/store/aos'
 import { ThemeToggle } from '@/components/theme-toggle'
+import { LocaleSwitcher } from './locale-switcher'
 import { Button } from '@/components/ui/button'
 import { Badge } from '@/components/ui/badge'
 import { Avatar, AvatarFallback } from '@/components/ui/avatar'
@@ -31,6 +32,7 @@ const TITLES: Record<ViewId, { title: string; crumb: string }> = {
   audit: { title: 'Audit-Protokoll', crumb: 'Betrieb / Audit' },
   api: { title: 'API & Webhooks', crumb: 'System / API' },
   settings: { title: 'Erweiterungen', crumb: 'System / Module' },
+  settings_global: { title: 'Einstellungen', crumb: 'System / Einstellungen' },
   setup: { title: 'Setup-Wizard', crumb: 'System / Setup' },
 }
 
@@ -74,6 +76,7 @@ export function TopBar() {
         </Button>
 
         <ThemeToggle />
+        <LocaleSwitcher />
 
         <Button variant="ghost" size="icon" className="relative" aria-label="Benachrichtigungen">
           <Bell className="size-4" />

src/components/aos/views/global-settings.tsx

@@ -0,0 +1,294 @@
+'use client'
+
+import { useState, useEffect } from 'react'
+import { useFetch } from '@/hooks/use-fetch'
+import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
+import { Badge } from '@/components/ui/badge'
+import { Button } from '@/components/ui/button'
+import { Input } from '@/components/ui/input'
+import { Label } from '@/components/ui/label'
+import { Skeleton } from '@/components/ui/skeleton'
+import { Separator } from '@/components/ui/separator'
+import { PageHeader } from '../primitives'
+import { useAos } from '@/store/aos'
+import { LOCALES } from '@/lib/i18n'
+import { Loader2, Save, Building2, FileText, Percent, Radar, FileCheck2, Languages, Lock, CheckCircle2 } from 'lucide-react'
+import { toast } from 'sonner'
+import { cn } from '@/lib/utils'
+
+interface SettingsData {
+  settings: Record<string, string>
+}
+
+export function GlobalSettingsView() {
+  const { data, loading, refetch } = useFetch<SettingsData>('/api/aos/settings')
+  const { locale, setLocale } = useAos()
+  const [form, setForm] = useState<Record<string, string>>({})
+  const [saving, setSaving] = useState(false)
+  const [dirty, setDirty] = useState(false)
+
+  useEffect(() => {
+    if (data?.settings) {
+      setForm(data.settings)
+      setDirty(false)
+    }
+  }, [data])
+
+  if (loading || !data) {
+    return (
+      <div className="space-y-6 p-4 md:p-6">
+        <Skeleton className="h-9 w-40" />
+        <Skeleton className="h-96" />
+      </div>
+    )
+  }
+
+  const update = (key: string, value: string) => {
+    setForm((f) => ({ ...f, [key]: value }))
+    setDirty(true)
+  }
+
+  const save = async () => {
+    setSaving(true)
+    const t = toast.loading('Einstellungen werden gespeichert…')
+    try {
+      const r = await fetch('/api/aos/settings', {
+        method: 'PATCH',
+        headers: { 'content-type': 'application/json' },
+        body: JSON.stringify(form),
+      })
+      const res = await r.json()
+      if (!r.ok) throw new Error(res.error || 'save failed')
+      toast.success(`${res.updated} Einstellungen gespeichert (Audit protokolliert)`, { id: t })
+      setDirty(false)
+      refetch()
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'Speichern fehlgeschlagen', { id: t })
+    } finally {
+      setSaving(false)
+    }
+  }
+
+  const Field = ({ label, k, mono, suffix }: { label: string; k: string; mono?: boolean; suffix?: string }) => (
+    <div className="space-y-1.5">
+      <Label className="text-xs">{label}</Label>
+      <div className="flex items-center gap-2">
+        <Input
+          value={form[k] ?? ''}
+          onChange={(e) => update(k, e.target.value)}
+          className={cn('text-sm', mono && 'font-mono')}
+        />
+        {suffix && <span className="shrink-0 text-xs text-muted-foreground">{suffix}</span>}
+      </div>
+    </div>
+  )
+
+  return (
+    <div className="space-y-6 p-4 md:p-6">
+      <PageHeader
+        title="Einstellungen"
+        description="Typisierte, datenbankgestützte Konfiguration. Alle Änderungen werden im Audit-Log protokolliert (Hash-Kette). Secrets werden AES-256-GCM verschlüsselt."
+        actions={
+          <Button onClick={save} disabled={saving || !dirty} className="gap-1.5">
+            {saving ? <Loader2 className="size-4 animate-spin" /> : <Save className="size-4" />}
+            Speichern
+          </Button>
+        }
+      />
+
+      {/* i18n / Locale */}
+      <Card>
+        <CardHeader className="pb-3">
+          <CardTitle className="flex items-center gap-2 text-sm">
+            <Languages className="size-4 text-muted-foreground" />
+            Sprache & Lokalisierung
+          </CardTitle>
+        </CardHeader>
+        <CardContent className="space-y-3">
+          <div className="space-y-1.5">
+            <Label className="text-xs">UI-Sprache (PRD §5.5: DE default, EN, TR)</Label>
+            <div className="flex gap-2">
+              {LOCALES.map((l) => (
+                <button
+                  key={l.id}
+                  onClick={() => setLocale(l.id)}
+                  className={cn(
+                    'flex items-center gap-2 rounded-md border px-3 py-2 text-xs transition',
+                    locale === l.id ? 'border-foreground/40 bg-foreground/5' : 'border-border hover:bg-muted/50'
+                  )}
+                >
+                  <span>{l.flag}</span>
+                  <span className="font-medium">{l.label}</span>
+                  {locale === l.id && <CheckCircle2 className="size-3" />}
+                </button>
+              ))}
+            </div>
+          </div>
+          <Separator />
+          <Field label="Standard-Sprache (neue Nutzer)" k="locale.default" />
+          <Field label="Verfügbare Sprachen (komma-getrennt)" k="locale.available" />
+          <p className="text-[11px] text-muted-foreground">
+            Zahlen-/Datumsformat folgt der UI-Sprache: DE = 1.234,56 € / 26.10.2026, EN = 1,234.56 € / 10/26/2026, TR = 1.234,56 ₺ / 26.10.2026
+          </p>
+        </CardContent>
+      </Card>
+
+      {/* Company data */}
+      <Card>
+        <CardHeader className="pb-3">
+          <CardTitle className="flex items-center gap-2 text-sm">
+            <Building2 className="size-4 text-muted-foreground" />
+            Unternehmens-Stammdaten
+          </CardTitle>
+        </CardHeader>
+        <CardContent className="grid grid-cols-1 gap-3 sm:grid-cols-2 lg:grid-cols-3">
+          <Field label="Firmenname" k="company.name" />
+          <Field label="Rechtsform" k="company.legalForm" />
+          <Field label="USt-IdNr." k="company.vatId" mono />
+          <Field label="Registergericht" k="company.registerCourt" />
+          <Field label="HRB-Nummer" k="company.registerNumber" mono />
+          <Field label="Stadt" k="company.city" />
+          <Field label="PLZ" k="company.zip" />
+          <Field label="Straße" k="company.street" />
+          <Field label="IBAN" k="company.bank" mono />
+          <Field label="BIC" k="company.bic" mono />
+        </CardContent>
+      </Card>
+
+      {/* Invoice numbering */}
+      <Card>
+        <CardHeader className="pb-3">
+          <CardTitle className="flex items-center gap-2 text-sm">
+            <FileText className="size-4 text-muted-foreground" />
+            Rechnungs-Nummernkreis (GoBD: lückenlos)
+          </CardTitle>
+        </CardHeader>
+        <CardContent className="grid grid-cols-1 gap-3 sm:grid-cols-3">
+          <Field label="Präfix" k="invoice.numberPrefix" mono />
+          <Field label="Jahr" k="invoice.numberYear" mono />
+          <Field label="Nächste Nummer" k="invoice.numberNext" mono />
+        </CardContent>
+        <CardContent className="pt-0">
+          <p className="rounded-md border border-dashed border-border p-2.5 text-[11px] text-muted-foreground">
+            Vorschau: <code className="font-mono">{form['invoice.numberPrefix'] ?? 'RE'}-{form['invoice.numberYear'] ?? '2026'}-{String(form['invoice.numberNext'] ?? '0042').padStart(4, '0')}</code>
+            — GoBD-konform, kein Löschen, Korrekturen als Storno (neue Zeile).
+          </p>
+        </CardContent>
+      </Card>
+
+      {/* Taxes */}
+      <Card>
+        <CardHeader className="pb-3">
+          <CardTitle className="flex items-center gap-2 text-sm">
+            <Percent className="size-4 text-muted-foreground" />
+            Steuersätze (Basispunkte)
+          </CardTitle>
+        </CardHeader>
+        <CardContent className="grid grid-cols-1 gap-3 sm:grid-cols-3">
+          <Field label="Standard-Steuersatz" k="tax.standardBp" suffix="Bp (1900 = 19%)" />
+          <Field label="Ermäßigter Steuersatz" k="tax.reducedBp" suffix="Bp (700 = 7%)" />
+          <Field label="Reverse Charge (Default)" k="tax.reverseChargeDefault" />
+        </CardContent>
+      </Card>
+
+      {/* Lead Finder */}
+      <Card>
+        <CardHeader className="pb-3">
+          <CardTitle className="flex items-center gap-2 text-sm">
+            <Radar className="size-4 text-muted-foreground" />
+            Leads Finder
+          </CardTitle>
+        </CardHeader>
+        <CardContent className="grid grid-cols-1 gap-3 sm:grid-cols-3">
+          <Field label="Such-Radius" k="leadFinder.radiusKm" suffix="km" />
+          <Field label="Kosten-Limit pro Lauf" k="leadFinder.costCapEur" suffix="€" />
+          <Field label="Auto-Genehmigung ab Score" k="leadFinder.autoApproveThreshold" suffix="/ 100" />
+        </CardContent>
+      </Card>
+
+      {/* E-Rechnung */}
+      <Card>
+        <CardHeader className="pb-3">
+          <CardTitle className="flex items-center gap-2 text-sm">
+            <FileCheck2 className="size-4 text-muted-foreground" />
+            E-Rechnung (ZUGFeRD / XRechnung)
+          </CardTitle>
+        </CardHeader>
+        <CardContent className="grid grid-cols-1 gap-3 sm:grid-cols-2">
+          <div className="space-y-1.5">
+            <Label className="text-xs">Format</Label>
+            <select
+              value={form['erechnung.format'] ?? 'zugferd'}
+              onChange={(e) => update('erechnung.format', e.target.value)}
+              className="h-9 w-full rounded border border-input bg-background px-3 text-sm outline-none focus-visible:ring-1 focus-visible:ring-ring"
+            >
+              <option value="zugferd">ZUGFeRD (Comfort)</option>
+              <option value="xrechnung">XRechnung (CII)</option>
+              <option value="both">Beide (Kunde wählt)</option>
+            </select>
+          </div>
+          <Field label="Leitweg-ID (öffentliche Kunden)" k="erechnung.leitwegId" mono />
+        </CardContent>
+        <CardContent className="pt-0">
+          <p className="text-[11px] text-muted-foreground">
+            Empfangs-Pflicht seit 2025, Versand-Pflicht ab 2027/2028 (umsatzabhängig). Validierung via <code className="font-mono">@e-invoice-eu/core</code> (EN 16931).
+          </p>
+        </CardContent>
+      </Card>
+
+      {/* Compliance / Retention */}
+      <Card>
+        <CardHeader className="pb-3">
+          <CardTitle className="flex items-center gap-2 text-sm">
+            <Lock className="size-4 text-muted-foreground" />
+            Compliance & Aufbewahrung
+          </CardTitle>
+        </CardHeader>
+        <CardContent className="grid grid-cols-1 gap-3 sm:grid-cols-2">
+          <Field label="Aufbewahrung Rechnungen" k="compliance.retentionInvoicesYears" suffix="Jahre (8)" />
+          <Field label="Aufbewahrung Geschäftsbriefe" k="compliance.retentionBusinessYears" suffix="Jahre (6)" />
+          <Field label="Encryption-Key Escrow" k="compliance.encryptionKeyEscrow" />
+        </CardContent>
+        <CardContent className="pt-0">
+          <div className="rounded-md border border-foreground/30 bg-foreground/5 p-3 text-[11px]">
+            <p className="flex items-center gap-1.5 font-medium text-foreground"><Lock className="size-3.5" />Secrets werden AES-256-GCM verschlüsselt</p>
+            <p className="mt-1 text-muted-foreground">
+              Der <code className="font-mono">ENCRYPTION_KEY</code> wird separat vom DB-Backup verwahrt. Ohne ihn sind SMTP, API-Keys und Signier-Schlüssel unwiederherstellbar.
+            </p>
+          </div>
+        </CardContent>
+      </Card>
+
+      {/* Mail config */}
+      <Card>
+        <CardHeader className="pb-3">
+          <CardTitle className="flex items-center gap-2 text-sm">
+            <FileText className="size-4 text-muted-foreground" />
+            E-Mail (SMTP/IMAP)
+          </CardTitle>
+        </CardHeader>
+        <CardContent className="grid grid-cols-1 gap-3 sm:grid-cols-2">
+          <Field label="SMTP-Host" k="mail.smtpHost" />
+          <Field label="SMTP-Port" k="mail.smtpPort" mono />
+          <Field label="IMAP-Host" k="mail.imapHost" />
+          <Field label="IMAP-Port" k="mail.imapPort" mono />
+        </CardContent>
+      </Card>
+
+      {/* Save bar */}
+      {dirty && (
+        <div className="sticky bottom-4 z-20 mx-auto flex max-w-md items-center gap-3 rounded-lg border border-foreground/30 bg-background p-3 shadow-lg">
+          <Badge variant="outline" className="gap-1 text-[10px]">
+            <span className="size-1.5 rounded-full bg-foreground" />
+            Ungespeichert
+          </Badge>
+          <span className="flex-1 text-xs text-muted-foreground">Änderungen werden im Audit-Log protokolliert.</span>
+          <Button size="sm" onClick={save} disabled={saving} className="gap-1.5">
+            {saving ? <Loader2 className="size-3.5 animate-spin" /> : <Save className="size-3.5" />}
+            Speichern
+          </Button>
+        </div>
+      )}
+    </div>
+  )
+}

src/hooks/use-i18n.ts

@@ -0,0 +1,11 @@
+'use client'
+
+import { useAos } from '@/store/aos'
+import { translate, type Locale } from '@/lib/i18n'
+
+// Returns a t() function bound to the current locale.
+export function useI18n() {
+  const locale = useAos((s) => s.locale) as Locale
+  const t = (key: string) => translate(key, locale)
+  return { t, locale }
+}

src/lib/i18n.ts

@@ -0,0 +1,174 @@
+// AOS i18n — German (default), English, Turkish (PRD §5.5)
+// All UI strings keyed, no literals in components.
+
+export type Locale = 'de' | 'en' | 'tr'
+
+export const LOCALES: { id: Locale; label: string; flag: string }[] = [
+  { id: 'de', label: 'Deutsch', flag: '🇩🇪' },
+  { id: 'en', label: 'English', flag: '🇬🇧' },
+  { id: 'tr', label: 'Türkçe', flag: '🇹🇷' },
+]
+
+type Dict = Record<string, string>
+
+const de: Dict = {
+  // Nav groups
+  'nav.overview': 'Übersicht',
+  'nav.sales': 'Vertrieb',
+  'nav.delivery': 'Lieferung',
+  'nav.operations': 'Betrieb',
+  'nav.system': 'System',
+  // Nav items
+  'nav.dashboard': 'Dashboard',
+  'nav.reporting': 'Reporting',
+  'nav.crm': 'CRM',
+  'nav.leads': 'Leads Finder',
+  'nav.estimates': 'Angebote',
+  'nav.projects': 'Projekte',
+  'nav.support': 'Support',
+  'nav.licenses': 'Lizenzen',
+  'nav.contracts': 'Verträge',
+  'nav.expenses': 'Ausgaben',
+  'nav.finance': 'Finanzen',
+  'nav.accounting': 'Buchhaltung',
+  'nav.audit': 'Audit-Protokoll',
+  'nav.api': 'API & Webhooks',
+  'nav.settings': 'Erweiterungen',
+  'nav.setup': 'Setup-Wizard',
+  'nav.settings_global': 'Einstellungen',
+  // Common
+  'common.search': 'Suchen…',
+  'common.new': 'Neu',
+  'common.save': 'Speichern',
+  'common.cancel': 'Abbrechen',
+  'common.close': 'Schließen',
+  'common.all': 'Alle',
+  'common.status': 'Status',
+  'common.actions': 'Aktion',
+  'common.date': 'Datum',
+  'common.amount': 'Betrag',
+  'common.customer': 'Kunde',
+  'common.loading': 'Lädt…',
+  // KPIs
+  'kpi.pipelineValue': 'Offene Pipeline',
+  'kpi.wonDeals': 'Gewonnene Deals',
+  'kpi.pendingLeads': 'Leads in Review',
+  'kpi.openProjects': 'Aktive Projekte',
+  'kpi.activeLicenses': 'Aktive Lizenzen',
+  'kpi.outstanding': 'Offene Forderungen',
+  'kpi.team': 'Team',
+  // Footer
+  'footer.compliance': 'GoBD / DSGVO',
+  'footer.selfHosted': 'self-hosted',
+  'footer.version': 'Version',
+  // Portal
+  'portal.title': 'Client-Portal',
+  'portal.selectCompany': 'Wähle dein Unternehmen',
+  'portal.isolated': 'projektbezogener Zugriff',
+}
+
+const en: Dict = {
+  'nav.overview': 'Overview',
+  'nav.sales': 'Sales',
+  'nav.delivery': 'Delivery',
+  'nav.operations': 'Operations',
+  'nav.system': 'System',
+  'nav.dashboard': 'Dashboard',
+  'nav.reporting': 'Reporting',
+  'nav.crm': 'CRM',
+  'nav.leads': 'Leads Finder',
+  'nav.estimates': 'Estimates',
+  'nav.projects': 'Projects',
+  'nav.support': 'Support',
+  'nav.licenses': 'Licenses',
+  'nav.contracts': 'Contracts',
+  'nav.expenses': 'Expenses',
+  'nav.finance': 'Finance',
+  'nav.accounting': 'Accounting',
+  'nav.audit': 'Audit Log',
+  'nav.api': 'API & Webhooks',
+  'nav.settings': 'Extensions',
+  'nav.setup': 'Setup Wizard',
+  'nav.settings_global': 'Settings',
+  'common.search': 'Search…',
+  'common.new': 'New',
+  'common.save': 'Save',
+  'common.cancel': 'Cancel',
+  'common.close': 'Close',
+  'common.all': 'All',
+  'common.status': 'Status',
+  'common.actions': 'Action',
+  'common.date': 'Date',
+  'common.amount': 'Amount',
+  'common.customer': 'Customer',
+  'common.loading': 'Loading…',
+  'kpi.pipelineValue': 'Open Pipeline',
+  'kpi.wonDeals': 'Won Deals',
+  'kpi.pendingLeads': 'Leads in Review',
+  'kpi.openProjects': 'Active Projects',
+  'kpi.activeLicenses': 'Active Licenses',
+  'kpi.outstanding': 'Outstanding',
+  'kpi.team': 'Team',
+  'footer.compliance': 'GoBD / GDPR',
+  'footer.selfHosted': 'self-hosted',
+  'footer.version': 'Version',
+  'portal.title': 'Client Portal',
+  'portal.selectCompany': 'Select your company',
+  'portal.isolated': 'project-scoped access',
+}
+
+const tr: Dict = {
+  'nav.overview': 'Genel Bakış',
+  'nav.sales': 'Satış',
+  'nav.delivery': 'Teslimat',
+  'nav.operations': 'Operasyon',
+  'nav.system': 'Sistem',
+  'nav.dashboard': 'Panel',
+  'nav.reporting': 'Raporlama',
+  'nav.crm': 'CRM',
+  'nav.leads': 'Müşteri Adayı Bulucu',
+  'nav.estimates': 'Teklifler',
+  'nav.projects': 'Projeler',
+  'nav.support': 'Destek',
+  'nav.licenses': 'Lisanslar',
+  'nav.contracts': 'Sözleşmeler',
+  'nav.expenses': 'Giderler',
+  'nav.finance': 'Finans',
+  'nav.accounting': 'Muhasebe',
+  'nav.audit': 'Denetim Günlüğü',
+  'nav.api': 'API & Webhook',
+  'nav.settings': 'Eklentiler',
+  'nav.setup': 'Kurulum Sihirbazı',
+  'nav.settings_global': 'Ayarlar',
+  'common.search': 'Ara…',
+  'common.new': 'Yeni',
+  'common.save': 'Kaydet',
+  'common.cancel': 'İptal',
+  'common.close': 'Kapat',
+  'common.all': 'Tümü',
+  'common.status': 'Durum',
+  'common.actions': 'İşlem',
+  'common.date': 'Tarih',
+  'common.amount': 'Tutar',
+  'common.customer': 'Müşteri',
+  'common.loading': 'Yükleniyor…',
+  'kpi.pipelineValue': 'Açık Pipeline',
+  'kpi.wonDeals': 'Kazanılan Anlaşmalar',
+  'kpi.pendingLeads': 'İncelemede Adaylar',
+  'kpi.openProjects': 'Aktif Projeler',
+  'kpi.activeLicenses': 'Aktif Lisanslar',
+  'kpi.outstanding': 'Açık Alacaklar',
+  'kpi.team': 'Ekip',
+  'footer.compliance': 'GoBD / KVKK',
+  'footer.selfHosted': 'self-hosted',
+  'footer.version': 'Sürüm',
+  'portal.title': 'Müşteri Portalı',
+  'portal.selectCompany': 'Şirketinizi seçin',
+  'portal.isolated': 'proje kapsamlı erişim',
+}
+
+const DICTS: Record<Locale, Dict> = { de, en, tr }
+
+export function translate(key: string, locale: Locale): string {
+  return DICTS[locale]?.[key] ?? DICTS.de[key] ?? key
+}

src/store/aos.ts

@@ -2,6 +2,7 @@
 
 import { create } from 'zustand'
 import { persist } from 'zustand/middleware'
+import type { Locale } from '@/lib/i18n'
 
 export type ViewId =
   | 'dashboard'
@@ -19,6 +20,7 @@ export type ViewId =
   | 'api'
   | 'reporting'
   | 'settings'
+  | 'settings_global'
   | 'setup'
 
 interface AosState {
@@ -37,6 +39,9 @@ interface AosState {
   portalCompanyId: string | null
   setPortalMode: (mode: boolean) => void
   setPortalCompany: (id: string | null) => void
+  // i18n (PRD §5.5: de default, en, tr)
+  locale: Locale
+  setLocale: (l: Locale) => void
 }
 
 export const useAos = create<AosState>()(
@@ -56,7 +61,9 @@ export const useAos = create<AosState>()(
       portalCompanyId: null,
       setPortalMode: (portalMode) => set({ portalMode }),
       setPortalCompany: (portalCompanyId) => set({ portalCompanyId }),
+      locale: 'de',
+      setLocale: (locale) => set({ locale }),
     }),
-    { name: 'aos-ui', partialize: (s) => ({ view: s.view, portalMode: s.portalMode, portalCompanyId: s.portalCompanyId }) }
+    { name: 'aos-ui', partialize: (s) => ({ view: s.view, portalMode: s.portalMode, portalCompanyId: s.portalCompanyId, locale: s.locale }) }
   )
 )