fix: demand Anfragen page shows own sent inquiries (demand perspective)

Replace supply-side mock data with demand-side conversations where the
logged-in user is the sender (right/dark) and verwalter replies are left.
List shows property name instead of tenant name.
New domain fields: propertyManagerName, propertyManagerCompany, propertyAddress.

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

src/domain/inquiry.ts

@@ -28,6 +28,9 @@ export interface Inquiry {
   tenantName: string
   tenantCompany?: string
   tenantEmail?: string
+  propertyManagerName?: string
+  propertyManagerCompany?: string
+  propertyAddress?: string
   subject: string
   message: string
   status?: InquiryStatus