fix(07): UAT fixes — SMTP test email, DKV routing, Exchange domain field

- SMTP: add test-to field, send real email via sendMail() instead of verify()
- SMTP: fix no_auth warning shown as error for open-relay servers
- DKV: register dkv-fleet in MODULE_REGISTRY (fixes "Modul nicht gefunden")
- DKV: add dynamic [category]/[moduleSlug]/settings + vehicles sub-routes
- DKV: settings/vehicles links use useParams for consistent URLs
- DKV: add gear icon settings link to module main page
- DKV: rename module to "DKV-Rechnung" in seed + translations
- DKV: add optional domain field for Exchange (WebCredentials 3rd arg)
- DKV: hide IMAP-only fields (Port/Verschlüsselung/Ordner) when Exchange selected
- DKV: hide Exchange-only field (Domain) when IMAP selected
- Prisma: add domain column to DkvModuleConfig

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

apps/api/src/dkv/dkv.service.ts

@@ -34,6 +34,7 @@ const CONFIG_SAFE_SELECT = {
   isActive: true,
   exportRecipient: true,
   vehicleFormatString: true,
+  domain: true,
   // encryptedInboxCreds: NEVER included — T-07-12
   createdAt: true,
   updatedAt: true,
@@ -156,6 +157,7 @@ export class DkvService {
       ...(dto.isActive !== undefined && { isActive: dto.isActive }),
       ...(dto.exportRecipient !== undefined && { exportRecipient: dto.exportRecipient }),
       ...(dto.vehicleFormatString !== undefined && { vehicleFormatString: dto.vehicleFormatString }),
+      ...(dto.domain !== undefined && { domain: dto.domain }),
       ...(encryptedInboxCreds !== undefined && { encryptedInboxCreds }),
     };
 
@@ -201,6 +203,7 @@ export class DkvService {
       encryption: dto.encryption,
       folder: dto.folder ?? 'INBOX',
       senderFilter: dto.senderFilter,
+      domain: dto.domain,
     };
 
     const provider = dto.protocol === 'exchange' ? this.exchangeProvider : this.imapProvider;