feat(email): global signature footer from the business profile (#1264)

The business profile already carried the operator's full issuer block —
address, phone, email, website, VAT id — but none of it reached an email.
Those columns only fed the quote/invoice PDF renderer, so every outgoing
mail footer was the fixed logo + company name + copyright line.

The signature is rendered by wrapEmailHtml and nowhere else, so no
template, no per-type send path and no queue row needed a change. Two new
columns on business_profile (migration 198) carry the toggle and one
free-text legal line; everything else is read from the address fields the
operator already maintains.

Default off, with a test pinning that the disabled path is byte-identical
to a no-profile install.

Includes three rounds of external review fixes: the plain-text MIME part
also carries the signature; string booleans ('false'/'0') no longer
invert the toggle; the status line stays silent rather than asserting
"off" while unauthorised or loading; and the preview's Text tab mirrors
the send path's htmlToText fallback.

Manual Messages replies deliberately keep no signature — they bypass the
wrapper by design — and the UI copy names that exception.

Closes #1264 (Part A)

frontend/src/i18n/locales/de.json

@@ -3855,7 +3855,10 @@
       "requiredFields": "Host, Port und Benutzername sind erforderlich.",
       "testOk": "Verbunden mit {{folder}} — {{messages}} Nachrichten, {{unseen}} ungelesen.",
       "testFailed": "Verbindung fehlgeschlagen."
-    }
+    },
+    "signatureOn": "Fusszeilen-Signatur ist an — Ihre Geschäftsadresse wird an automatische E-Mails angehängt. Antworten, die Sie unter Nachrichten schreiben, werden unverändert gesendet.",
+    "signatureOff": "Fusszeilen-Signatur ist aus — E-Mails zeigen nur Logo und Firmenname.",
+    "signatureEdit": "Im Geschäftsprofil bearbeiten"
   },
   "cms": {
     "title": "CMS-Seiten",
@@ -6113,7 +6116,19 @@
     "logoUploadedToast": "PDF-Logo hochgeladen.",
     "logoConfirmClear": "PDF-Logo entfernen? Der Renderer greift dann auf das Branding-Logo zurück, sofern eines hinterlegt ist.",
     "logoClearedToast": "PDF-Logo entfernt.",
-    "bankUpdatedToast": "Bankverbindung aktualisiert."
+    "bankUpdatedToast": "Bankverbindung aktualisiert.",
+    "emailSignature": {
+      "title": "E-Mail-Signatur",
+      "subtitle": "Hängt Ihre Firmendaten an die Fusszeile jeder E-Mail an, die diese Installation versendet. Wird aus den Adress- und Kontaktfeldern oben gebildet — nichts wird doppelt erfasst.",
+      "toggle": "Signatur in E-Mail-Fusszeilen anzeigen",
+      "toggleHelp": "Wenn aus, behalten E-Mails die schlichte Fusszeile mit Logo und Firmenname. Gilt für jede automatische E-Mail — Galerie-Benachrichtigungen, Offerten, Rechnungen, Erinnerungen — sowie für Testversand und Vorschau. Antworten, die Sie selbst unter Nachrichten schreiben, werden unverändert gesendet und erhalten keine Signatur.",
+      "extra": "Rechtliche Zeile (optional)",
+      "extraPlaceholder": "Handelsregister Vaduz FL-0002.123.456-7",
+      "extraHelp": "Registernummer, Haftungsausschluss oder jede Zeile ohne eigenes Feld. Reiner Text, maximal 500 Zeichen.",
+      "previewTitle": "Vorschau der Fusszeile",
+      "previewOff": "Signatur ist aus — E-Mails zeigen nur Logo und Firmenname.",
+      "previewEmpty": "Signatur ist an, aber alle Felder oben sind leer — es wird nichts an die Fusszeile angehängt."
+    }
   },
   "crmSettings": {
     "savedToast": "CRM-Einstellungen gespeichert.",

frontend/src/i18n/locales/en.json

@@ -3368,7 +3368,10 @@
       "requiredFields": "Host, port and username are required.",
       "testOk": "Connected to {{folder}} — {{messages}} messages, {{unseen}} unread.",
       "testFailed": "Connection failed."
-    }
+    },
+    "signatureOn": "Footer signature is on — your business address is appended to automatic emails. Replies you write in Messages are sent as typed.",
+    "signatureOff": "Footer signature is off — emails show the logo and company name only.",
+    "signatureEdit": "Edit in Business profile"
   },
   "cms": {
     "title": "CMS Pages",
@@ -6112,7 +6115,19 @@
     "logoUploadedToast": "PDF logo uploaded.",
     "logoConfirmClear": "Remove the PDF logo? The renderer will fall back to the Branding logo if one is set.",
     "logoClearedToast": "PDF logo removed.",
-    "bankUpdatedToast": "Bank account updated."
+    "bankUpdatedToast": "Bank account updated.",
+    "emailSignature": {
+      "title": "Email signature",
+      "subtitle": "Append your company details to the footer of every email this installation sends. Built from the address and contact fields above — nothing is duplicated.",
+      "toggle": "Show signature in email footers",
+      "toggleHelp": "When off, emails keep the plain logo + company name footer. Applies to every automatic email — gallery notices, quotes, invoices, reminders — plus test sends and previews. Replies you write yourself in Messages are sent as typed and do not get the signature.",
+      "extra": "Legal line (optional)",
+      "extraPlaceholder": "Handelsregister Vaduz FL-0002.123.456-7",
+      "extraHelp": "Registration number, disclaimer or any line with no field of its own. Plain text, up to 500 characters.",
+      "previewTitle": "Footer preview",
+      "previewOff": "Signature is off — emails show the logo and company name only.",
+      "previewEmpty": "Signature is on but every field above is blank — nothing will be added to the footer."
+    }
   },
   "crmSettings": {
     "savedToast": "CRM settings saved.",

frontend/src/pages/admin/EmailConfigPage.tsx

@@ -23,10 +23,12 @@ import { ReceivedEmailsPanel } from '../../components/admin/ReceivedEmailsPanel'
 import { IncomingMailConfigCard } from '../../components/admin/IncomingMailConfigCard';
 import { CustomerMailboxCard } from '../../components/admin/CustomerMailboxCard';
 import { Palette, RefreshCw, Info } from 'lucide-react';
+import { Link } from 'react-router-dom';
 import { useQuery, useMutation } from '@tanstack/react-query';
 import { useModal, useMutationWithToast } from '../../hooks';
 import { emailService, type EmailConfig, type EmailTemplate, type EmailTemplateTranslation } from '../../services/email.service';
 import { settingsService } from '../../services/settings.service';
+import { businessProfileService } from '../../services/businessProfile.service';
 import { useTranslation } from 'react-i18next';
 import { SUPPORTED_LANGUAGES } from "../../components/common/LanguageSelector.tsx";
 import { useFeatureFlags, type FeatureKey } from '../../contexts/FeatureFlagsContext';
@@ -210,6 +212,27 @@ export const EmailConfigPage: React.FC = () => {
     tls_reject_unauthorized: true
   });
 
+  // Migration 198 — whether the global footer signature is on. Read-only
+  // here; the toggle itself lives on Settings → Business profile.
+  //
+  // This tab is reachable with `email.view`, but GET /admin/business-profile
+  // requires `settings.view` / `settings.banking`. An email-only role gets a
+  // 403, and reporting that as "signature is off" would be stating something
+  // false about a mail they are about to send — so an unreadable profile
+  // renders nothing at all rather than a guess (#1264 review).
+  const { data: businessProfile, isError, isPending } = useQuery({
+    queryKey: ['business-profile'],
+    queryFn: () => businessProfileService.get(),
+    enabled: activeTab === 'smtp',
+    retry: false,
+  });
+  // Pending counts as unknown too. The other queries on this tab are often
+  // cached and paint first, so `?? false` announced "signature is off" for
+  // as long as this request was in flight — a wrong statement about a mail
+  // the admin is about to send, not merely a slow one.
+  const signatureUnknown = isError || isPending || !businessProfile;
+  const signatureEnabled = businessProfile?.profile?.emailSignatureEnabled ?? false;
+
   // Fetch SMTP config
   const { isLoading: configLoading } = useQuery({
     queryKey: ['email-config'],
@@ -536,6 +559,24 @@ export const EmailConfigPage: React.FC = () => {
       {/* SMTP Settings Tab */}
       {activeTab === 'smtp' && (
         <div className="grid grid-cols-1 lg:grid-cols-2 gap-6">
+          {/* The footer signature (migration 198) is applied by the email
+              wrapper to every send from this page, but it's configured on
+              the Business profile — point at it from where the mail is set
+              up rather than making the operator hunt for it. */}
+          {!signatureUnknown && (
+          <div className="lg:col-span-2 flex items-start gap-2 rounded-md border border-neutral-200 dark:border-neutral-700 bg-neutral-50 dark:bg-neutral-800/60 p-3 text-sm text-neutral-600 dark:text-neutral-400">
+            <Info className="w-4 h-4 mt-0.5 shrink-0" />
+            <span>
+              {signatureEnabled
+                ? t('email.signatureOn', 'Footer signature is on — your business address is appended to automatic emails. Replies you write in Messages are sent as typed.')
+                : t('email.signatureOff', 'Footer signature is off — emails show the logo and company name only.')}
+              {' '}
+              <Link to="/admin/settings?tab=businessProfile" className="underline hover:no-underline" style={{ color: 'var(--color-accent)' }}>
+                {t('email.signatureEdit', 'Edit in Business profile')}
+              </Link>
+            </span>
+          </div>
+          )}
           <Card padding="md">
             <h2 className="text-lg font-semibold text-neutral-900 dark:text-neutral-100 mb-4">{t('email.smtpConfiguration')}</h2>
 

frontend/src/pages/admin/settings/SettingsBusinessProfilePage.tsx

@@ -8,7 +8,7 @@
 import React, { useEffect, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
-import { Plus, Trash2, Star, Pencil, Save, Clock, Copy } from 'lucide-react';
+import { Plus, Trash2, Star, Pencil, Save, Clock, Copy, Mail } from 'lucide-react';
 import {
   businessProfileService,
   type BusinessProfile,
@@ -305,6 +305,58 @@ export const SettingsBusinessProfilePage: React.FC = () => {
         </div>
       </Card>
 
+      {/* Global email footer signature (migration 198, issue #1264).
+          Rendered by wrapEmailHtml only, so flipping this toggle changes
+          the footer of EVERY outgoing mail — transactional, preview, test
+          and manual — without any per-template edit. Every value except
+          the legal line below comes from the fields already on this page. */}
+      <Card>
+        <div className="flex items-center gap-2 mb-1">
+          <Mail className="w-5 h-5 text-neutral-500" />
+          <h3 className="font-semibold text-neutral-900 dark:text-neutral-100">
+            {t('businessProfile.emailSignature.title', 'Email signature')}
+          </h3>
+        </div>
+        <p className="text-sm text-neutral-600 dark:text-neutral-400 mb-4">
+          {t('businessProfile.emailSignature.subtitle',
+            'Append your company details to the footer of every email this installation sends. Built from the address and contact fields above — nothing is duplicated.')}
+        </p>
+
+        <PdfToggleRow
+          label={t('businessProfile.emailSignature.toggle', 'Show signature in email footers') as string}
+          description={t('businessProfile.emailSignature.toggleHelp',
+            'When off, emails keep the plain logo + company name footer. Applies to every automatic email — gallery notices, quotes, invoices, reminders — plus test sends and previews. Replies you write yourself in Messages are sent as typed and do not get the signature.') as string}
+          enabled={profile.emailSignatureEnabled}
+          onChange={(v) => setProfile({ ...profile, emailSignatureEnabled: v })}
+        />
+
+        <div className="mt-4">
+          <label className="block text-sm font-medium text-neutral-700 dark:text-neutral-300 mb-1">
+            {t('businessProfile.emailSignature.extra', 'Legal line (optional)')}
+          </label>
+          <textarea
+            rows={3}
+            maxLength={500}
+            value={profile.emailSignatureExtra}
+            onChange={(e) => setProfile({ ...profile, emailSignatureExtra: e.target.value })}
+            placeholder={t('businessProfile.emailSignature.extraPlaceholder',
+              'Handelsregister Vaduz FL-0002.123.456-7') as string}
+            className="w-full rounded-md border border-neutral-300 dark:border-neutral-600 bg-white dark:bg-neutral-800 px-3 py-2 text-sm text-neutral-900 dark:text-neutral-100"
+          />
+          <p className="mt-1 text-xs text-neutral-500 dark:text-neutral-400">
+            {t('businessProfile.emailSignature.extraHelp',
+              'Registration number, disclaimer or any line with no field of its own. Plain text, up to 500 characters.')}
+          </p>
+        </div>
+
+        <div className="mt-4 pt-4 border-t border-neutral-200 dark:border-neutral-700">
+          <p className="text-xs font-medium text-neutral-500 dark:text-neutral-400 mb-2 uppercase tracking-wide">
+            {t('businessProfile.emailSignature.previewTitle', 'Footer preview')}
+          </p>
+          <EmailSignaturePreview profile={profile} />
+        </div>
+      </Card>
+
       {/* Disclaimer banner for QR-bill / IBAN data. picpeak renders
           what the operator types — it cannot validate IBAN/BIC, QR-IID
           or scan-compatibility with any specific bank's e-banking app.
@@ -361,6 +413,64 @@ const PdfToggleRow: React.FC<PdfToggleRowProps> = ({ label, description, enabled
   </label>
 );
 
+/**
+ * Read-only render of the email footer signature (migration 198).
+ *
+ * Deliberately mirrors `renderEmailSignature` in the backend's
+ * emailProcessor: same field order, same middle-dot separators, same
+ * omit-when-empty rule. It is a preview, not a second renderer — the mail
+ * itself is always built server-side.
+ */
+const EmailSignaturePreview: React.FC<{ profile: BusinessProfile }> = ({ profile }) => {
+  const { t, i18n } = useTranslation();
+
+  if (!profile.emailSignatureEnabled) {
+    return (
+      <p className="text-sm text-neutral-500 dark:text-neutral-400 italic">
+        {t('businessProfile.emailSignature.previewOff', 'Signature is off — emails show the logo and company name only.')}
+      </p>
+    );
+  }
+
+  // "LI-9494 Schaan / Liechtenstein" — the same shape the PDF issuer
+  // block uses, assembled identically on the backend.
+  const cc = profile.countryCode ? profile.countryCode.toUpperCase() : '';
+  const pc = profile.postalCode || '';
+  const left = [cc && pc ? `${cc}-${pc}` : (pc || cc), profile.city || ''].filter(Boolean).join(' ');
+  const cityCountry = [left, profile.countryName || ''].filter(Boolean).join(' / ');
+
+  const addressLines = [profile.addressLine1, profile.addressLine2, cityCountry]
+    .map((l) => (l || '').trim())
+    .filter(Boolean);
+  const contacts = [profile.phone, profile.mobile, profile.email, profile.website]
+    .map((c) => (c || '').trim())
+    .filter(Boolean);
+  const vatLabel = i18n.language?.startsWith('de') ? 'USt-IdNr.' : 'VAT ID';
+
+  const isEmpty = !profile.companyName && !addressLines.length && !contacts.length
+    && !profile.vatId && !profile.emailSignatureExtra;
+  if (isEmpty) {
+    return (
+      <p className="text-sm text-amber-700 dark:text-amber-400">
+        {t('businessProfile.emailSignature.previewEmpty',
+          'Signature is on but every field above is blank — nothing will be added to the footer.')}
+      </p>
+    );
+  }
+
+  return (
+    <div data-testid="email-signature-preview" className="rounded-md bg-neutral-50 dark:bg-neutral-800/60 p-3 text-center text-xs text-neutral-600 dark:text-neutral-400 space-y-1">
+      {profile.companyName && <p>{profile.companyName}</p>}
+      {addressLines.length > 0 && <p>{addressLines.join(' \u00b7 ')}</p>}
+      {contacts.length > 0 && <p>{contacts.join(' \u00b7 ')}</p>}
+      {profile.vatId && <p>{vatLabel}: {profile.vatId}</p>}
+      {profile.emailSignatureExtra && (
+        <p className="text-[11px] whitespace-pre-line">{profile.emailSignatureExtra}</p>
+      )}
+    </div>
+  );
+};
+
 /**
  * Per-weekday business-hours editor (migration 114). Google-style: each
  * weekday holds zero or more {start,end} blocks, so a day can be closed

frontend/src/pages/admin/settings/__tests__/emailSignatureCard.test.tsx

@@ -0,0 +1,164 @@
+/**
+ * Settings → Business profile — email signature card (migration 198, #1264).
+ *
+ * The preview here mirrors the backend's `renderEmailSignature`, so the
+ * cases worth pinning are the ones where the two could silently drift:
+ * the "LI-9494 Schaan / Liechtenstein" city line, the middle-dot joins,
+ * and the omit-when-empty rule. Plus the two states an operator can land
+ * in and misread — signature off, and signature on with a blank profile.
+ */
+import { render, screen, within } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { vi } from 'vitest';
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+
+import type { BusinessProfile } from '../../../../services/businessProfile.service';
+
+vi.mock('react-i18next', async () => {
+  const actual = await vi.importActual<typeof import('react-i18next')>('react-i18next');
+  return {
+    ...actual,
+    useTranslation: () => ({
+      t: (k: string, fb?: unknown) => (typeof fb === 'string' ? fb : k),
+      i18n: { language: 'en' },
+    }),
+  };
+});
+
+vi.mock('react-toastify', () => ({ toast: { success: vi.fn(), error: vi.fn() } }));
+
+const baseProfile: BusinessProfile = {
+  id: 1,
+  companyName: 'Müller Fotografie GmbH',
+  addressLine1: 'Bahnhofstrasse 1',
+  addressLine2: '',
+  postalCode: '9494',
+  city: 'Schaan',
+  state: '',
+  countryCode: 'LI',
+  countryName: 'Liechtenstein',
+  phone: '+41 79 123 45 67',
+  mobile: '',
+  email: '[email protected]',
+  website: 'example.com',
+  vatId: 'CHE-123.456.789',
+  taxId: '',
+  vatLabel: 'MwSt.',
+  vatRateDefault: null,
+  defaultHourlyRateMinor: null,
+  defaultCurrency: 'CHF',
+  defaultLocale: 'de',
+  defaultQrFormat: 'none',
+  footerLine: '',
+  logoPath: '',
+  pdfFontTtfPath: '',
+  pdfFontFamily: null,
+  pdfShowLogo: true,
+  pdfShowCompanyName: true,
+  pdfCompanyNameInline: false,
+  pdfLogoHeight: 56,
+  pdfFoldingMarks: 'none',
+  pdfQuoteShowNetDays: false,
+  pdfQuoteShowSkonto: false,
+  timezone: null,
+  businessHours: null,
+  scheduledEmailFloorEnabled: true,
+  emailSignatureEnabled: true,
+  emailSignatureExtra: 'Handelsregister Vaduz',
+  createdAt: '2026-01-01T00:00:00Z',
+  updatedAt: '2026-01-01T00:00:00Z',
+};
+
+let profileFixture: BusinessProfile = baseProfile;
+
+vi.mock('../../../../services/businessProfile.service', () => ({
+  businessProfileService: {
+    get: vi.fn(async () => ({ profile: profileFixture, bankAccounts: [] })),
+    update: vi.fn(async () => ({ profile: profileFixture, bankAccounts: [] })),
+    listBankAccounts: vi.fn(async () => ({ bankAccounts: [] })),
+    createBankAccount: vi.fn(),
+    updateBankAccount: vi.fn(),
+    deleteBankAccount: vi.fn(),
+    uploadLogo: vi.fn(),
+    clearLogo: vi.fn(),
+  },
+}));
+
+import { SettingsBusinessProfilePage } from '../SettingsBusinessProfilePage';
+
+function renderPage() {
+  const qc = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+  return render(
+    <QueryClientProvider client={qc}>
+      <SettingsBusinessProfilePage />
+    </QueryClientProvider>
+  );
+}
+
+describe('email signature card', () => {
+  beforeEach(() => {
+    profileFixture = { ...baseProfile };
+  });
+
+  it('renders the signature preview from the address fields above', async () => {
+    renderPage();
+
+    // Scoped to the preview block — the legal line also lives in the
+    // textarea above it, and the company name in the form fields.
+    const preview = within(await screen.findByTestId('email-signature-preview'));
+
+    expect(preview.getByText('Müller Fotografie GmbH')).toBeInTheDocument();
+    // City line uses the PDF issuer shape, not a raw "9494 Schaan".
+    expect(preview.getByText('Bahnhofstrasse 1 · LI-9494 Schaan / Liechtenstein')).toBeInTheDocument();
+    // Empty mobile is omitted rather than producing a doubled separator.
+    expect(preview.getByText('+41 79 123 45 67 · [email protected] · example.com')).toBeInTheDocument();
+    expect(preview.getByText('VAT ID: CHE-123.456.789')).toBeInTheDocument();
+    expect(preview.getByText('Handelsregister Vaduz')).toBeInTheDocument();
+  });
+
+  it('explains the off state instead of showing a stale preview', async () => {
+    profileFixture = { ...baseProfile, emailSignatureEnabled: false };
+    renderPage();
+
+    expect(
+      await screen.findByText('Signature is off — emails show the logo and company name only.')
+    ).toBeInTheDocument();
+    expect(screen.queryByTestId('email-signature-preview')).not.toBeInTheDocument();
+  });
+
+  it('warns when the signature is on but every field is blank', async () => {
+    profileFixture = {
+      ...baseProfile,
+      companyName: '', addressLine1: '', addressLine2: '', postalCode: '', city: '',
+      countryCode: '', countryName: '', phone: '', mobile: '', email: '', website: '',
+      vatId: '', emailSignatureExtra: '',
+    };
+    renderPage();
+
+    expect(
+      await screen.findByText(
+        'Signature is on but every field above is blank — nothing will be added to the footer.'
+      )
+    ).toBeInTheDocument();
+  });
+
+  it('toggling off updates the preview without a save', async () => {
+    renderPage();
+    await screen.findByText('Footer preview');
+
+    await userEvent.click(screen.getByRole('switch', { name: /Show signature in email footers/i }));
+
+    expect(
+      screen.getByText('Signature is off — emails show the logo and company name only.')
+    ).toBeInTheDocument();
+  });
+
+  it('caps the legal line at 500 characters', async () => {
+    renderPage();
+
+    const textarea = (await screen.findByPlaceholderText(
+      'Handelsregister Vaduz FL-0002.123.456-7'
+    )) as HTMLTextAreaElement;
+    expect(textarea.maxLength).toBe(500);
+  });
+});

frontend/src/services/businessProfile.service.ts

@@ -94,6 +94,16 @@ export interface BusinessProfile {
    *  (migration 114). Defaults true. When off, scheduled emails send at
    *  their requested instant regardless of `businessHours`. */
   scheduledEmailFloorEnabled: boolean;
+  /** Global email footer signature master switch (migration 198). When
+   *  on, `wrapEmailHtml` appends the issuer block below — address,
+   *  contacts, VAT id and `emailSignatureExtra` — to the footer of EVERY
+   *  outgoing mail: transactional, preview, test and manual alike.
+   *  Defaults false so an upgraded install's footer is unchanged. */
+  emailSignatureEnabled: boolean;
+  /** Free-text legal line under the signature (Handelsregister /
+   *  registration number / disclaimer). Plain text, max 500 chars —
+   *  rendered escaped with newlines turned into <br>. Migration 198. */
+  emailSignatureExtra: string;
   createdAt: string;
   updatedAt: string;
 }