feat(calendar): add domain field and test-connection button to Exchange sources

- Prisma: domain String? added to CalendarSource model (db push applied)
- DTOs: domain in CreateCalendarSourceDto, UpdateCalendarSourceDto, new TestCalendarSourceConfigDto
- Service: domain in SOURCE_SAFE_SELECT, addSource, updateSource; new testConnectionFromConfig method
- Controller: POST /calendar/sources/test-config (before :id routes to avoid collision)
- ExchangeProvider: domain in all source interfaces; passed as 3rd arg to EWS WebCredentials
- Frontend: domain in CalendarSource/CreateSourcePayload/UpdateSourcePayload; testSourceConfig API fn
- Form: domain field (Exchange-only), "Test connection" button with idle/loading/success/error states
- i18n: de+en keys for formFieldDomain, formFieldDomainHint, formTestConnection, formTesting, formTestSuccess, formTestFailed

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

apps/web/src/components/settings/calendar-source-form.tsx

@@ -3,6 +3,7 @@
 import { useCallback, useState } from 'react';
 import { useTranslations } from 'next-intl';
 import type { CreateSourcePayload } from '@/lib/calendar-api';
+import { testSourceConfig } from '@/lib/calendar-api';
 
 /**
  * 8-color palette for calendar sources (UI-SPEC).
@@ -69,6 +70,8 @@ export function CalendarSourceForm({
   const [exchangeMode, setExchangeMode] = useState(
     initialValues?.exchangeMode ?? 'graph',
   );
+  const [domain, setDomain] = useState(initialValues?.domain ?? '');
+  const [testStatus, setTestStatus] = useState<'idle' | 'loading' | 'success' | 'error'>('idle');
   const [color, setColor] = useState(
     initialValues?.color ?? SOURCE_COLOR_PALETTE[0].value,
   );
@@ -103,6 +106,24 @@ export function CalendarSourceForm({
     url.trim() !== '' &&
     !urlError;
 
+  const handleTest = useCallback(async () => {
+    if (!validateUrl(url)) return;
+    setTestStatus('loading');
+    try {
+      const result = await testSourceConfig({
+        type,
+        url: url.trim(),
+        username: username.trim() || undefined,
+        password: password || undefined,
+        exchangeMode: isExchange ? exchangeMode : undefined,
+        domain: isExchange && domain.trim() ? domain.trim() : undefined,
+      });
+      setTestStatus(result.success ? 'success' : 'error');
+    } catch {
+      setTestStatus('error');
+    }
+  }, [type, url, username, password, exchangeMode, domain, isExchange, validateUrl]);
+
   const handleSubmit = useCallback(
     async (e: React.FormEvent) => {
       e.preventDefault();
@@ -122,14 +143,15 @@ export function CalendarSourceForm({
         if (password) payload.password = password;
       }
 
-      // Include exchangeMode for Exchange type
+      // Include exchangeMode and domain for Exchange type
       if (isExchange) {
         payload.exchangeMode = exchangeMode;
+        if (domain.trim()) payload.domain = domain.trim();
       }
 
       await onSave(payload);
     },
-    [name, type, url, username, password, exchangeMode, color, isICS, isExchange, onSave, validateUrl],
+    [name, type, url, username, password, exchangeMode, domain, color, isICS, isExchange, onSave, validateUrl],
   );
 
   return (
@@ -194,6 +216,23 @@ export function CalendarSourceForm({
         </div>
       )}
 
+      {/* Domain (Exchange EWS only) */}
+      {isExchange && (
+        <div>
+          <label htmlFor="exchange-domain" className="mb-1 block text-sm text-foreground">
+            {t('calendar.formFieldDomain')}
+          </label>
+          <input
+            id="exchange-domain"
+            type="text"
+            placeholder={t('calendar.formFieldDomainHint')}
+            className="h-9 w-full max-w-md rounded border border-border bg-background px-3 text-sm text-foreground"
+            value={domain}
+            onChange={(e) => setDomain(e.target.value)}
+          />
+        </div>
+      )}
+
       {/* URL */}
       <div>
         <label htmlFor="source-url" className="mb-1 block text-sm text-foreground">
@@ -282,7 +321,7 @@ export function CalendarSourceForm({
       </div>
 
       {/* Actions */}
-      <div className="flex gap-3 pt-2">
+      <div className="flex flex-wrap gap-3 pt-2">
         <button
           type="submit"
           data-testid="source-form-submit"
@@ -291,6 +330,15 @@ export function CalendarSourceForm({
         >
           {isSaving ? t('calendar.formSaving') : t('calendar.formSave')}
         </button>
+        <button
+          type="button"
+          data-testid="source-form-test"
+          disabled={!isFormValid || testStatus === 'loading'}
+          onClick={handleTest}
+          className="rounded border border-border px-4 py-2 text-sm text-foreground transition-colors hover:bg-muted disabled:opacity-50 disabled:cursor-not-allowed"
+        >
+          {testStatus === 'loading' ? t('calendar.formTesting') : t('calendar.formTestConnection')}
+        </button>
         <button
           type="button"
           onClick={onCancel}
@@ -299,6 +347,12 @@ export function CalendarSourceForm({
           {t('calendar.formCancel')}
         </button>
       </div>
+      {testStatus === 'success' && (
+        <p className="text-sm text-green-600 dark:text-green-400">{t('calendar.formTestSuccess')}</p>
+      )}
+      {testStatus === 'error' && (
+        <p className="text-sm text-destructive">{t('calendar.formTestFailed')}</p>
+      )}
     </form>
   );
 }

apps/web/src/lib/calendar-api.ts

@@ -22,6 +22,7 @@ export interface CalendarSource {
   name: string;
   type: 'caldav' | 'ics' | 'exchange';
   exchangeMode?: string | null;
+  domain?: string | null;
   url: string;
   username?: string | null;
   color?: string | null;
@@ -59,6 +60,7 @@ export interface CreateSourcePayload {
   username?: string;
   password?: string;
   exchangeMode?: string;
+  domain?: string;
   color?: string;
 }
 
@@ -73,6 +75,7 @@ export interface UpdateSourcePayload {
   username?: string;
   password?: string;
   exchangeMode?: string;
+  domain?: string;
   color?: string;
   isVisible?: boolean;
 }
@@ -138,6 +141,28 @@ export async function deleteSource(id: string): Promise<void> {
   if (!res.ok) throw new Error('Failed to delete calendar source');
 }
 
+/**
+ * Test a calendar configuration without saving it.
+ * POST /calendar/sources/test-config
+ */
+export async function testSourceConfig(config: {
+  type: string;
+  url: string;
+  username?: string;
+  password?: string;
+  exchangeMode?: string;
+  domain?: string;
+}): Promise<{ success: boolean; error?: string }> {
+  const res = await fetch(`${API_URL}/calendar/sources/test-config`, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    credentials: 'include',
+    body: JSON.stringify(config),
+  });
+  if (!res.ok) throw new Error('Test request failed');
+  return res.json();
+}
+
 /**
  * Test connection to a calendar source.
  * POST /calendar/sources/:id/test

apps/web/src/messages/de.json

@@ -202,6 +202,12 @@
       "formFieldPassword": "Passwort",
       "formFieldColor": "Farbe",
       "formFieldExchangeMode": "Exchange-Modus",
+      "formFieldDomain": "Domain",
+      "formFieldDomainHint": "Windows-Domain (z.B. FIRMA)",
+      "formTestConnection": "Verbindung testen",
+      "formTesting": "Teste...",
+      "formTestSuccess": "Verbindung erfolgreich",
+      "formTestFailed": "Verbindung fehlgeschlagen",
       "formSave": "Speichern",
       "formSaving": "Wird gespeichert...",
       "formCancel": "Abbrechen",

apps/web/src/messages/en.json

@@ -202,6 +202,12 @@
       "formFieldPassword": "Password",
       "formFieldColor": "Color",
       "formFieldExchangeMode": "Exchange Mode",
+      "formFieldDomain": "Domain",
+      "formFieldDomainHint": "Windows domain (e.g. COMPANY)",
+      "formTestConnection": "Test connection",
+      "formTesting": "Testing...",
+      "formTestSuccess": "Connection successful",
+      "formTestFailed": "Connection failed",
       "formSave": "Save",
       "formSaving": "Saving...",
       "formCancel": "Cancel",