feat(messages): unified conversation inbox — connect demand ↔ supply, offers reach the seeker

Phase 1 of the messaging rework: one conversation/thread model (Inquiry) is the single source of truth, read perspectivally by both sides.

- domain/inquiry: add kind (INQUIRY|OFFER), tenantOrgId (demand org), offeredPropertyIds
- provider/service: InquiryFilters gains tenantOrgId+kind; new createInquiry (demand→supply) & createOffer (supply→demand) materialize threads; addMessage bumps unread; reply carries senderType (tenant vs supply_user)
- hooks: useCreateInquiry, useCreateOffer; reply payload carries sender perspective
- demand: InquiryQuickDialog → createInquiry via provider (session-based tenant/org, no hardcode); Anfragen.tsx reads via React Query (tenantOrgId) with Gesendet/Erhalten tabs, replies via provider, shows offered properties for OFFER threads; inquiryStore reduced to dialog-only (removes Zustand server-data island)
- supply: OfferChatComposer send now materializes an OFFER conversation into the seeker's inbox (routed via latentNeed.tenantOrgId); Anfragencenter gains a "Gesendet" tab; ActiveInquiriesTab filters by perspective (org + kind)
- seed: merge demand inquiries with tenantOrgId=org-mobimo + 2 OFFER seeds; provider seeds from both sets

Closes the loop: a sent inquiry reaches the Verwaltung and a sent offer reaches the Nachfrager — both answerable in one thread.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/services/inquiryService.ts

@@ -1,6 +1,6 @@
 import { MockupInquiryProvider } from '../provider/MockupInquiryProvider'
-import type { InquiryFilters } from '../provider/IInquiryProvider'
-import type { Inquiry, Attachment } from '../domain/inquiry'
+import type { InquiryFilters, CreateInquiryInput, CreateOfferInput } from '../provider/IInquiryProvider'
+import type { Inquiry, Attachment, InquiryMessage } from '../domain/inquiry'
 import type { ListResponse, ItemResponse } from './types'
 import { throwServiceError } from './errors'
 
@@ -10,6 +10,8 @@ export interface InquiryReplyPayload {
   subject?: string
   body: string
   attachments?: Attachment[]
+  senderType?: InquiryMessage['senderType']   // default 'supply_user'
+  senderName?: string
 }
 
 export const inquiryService = {
@@ -31,14 +33,32 @@ export const inquiryService = {
     }
   },
 
+  async createInquiry(input: CreateInquiryInput): Promise<ItemResponse<Inquiry>> {
+    try {
+      const data = await provider.createInquiry(input)
+      return { data }
+    } catch (err) {
+      throwServiceError(err)
+    }
+  },
+
+  async createOffer(input: CreateOfferInput): Promise<ItemResponse<Inquiry>> {
+    try {
+      const data = await provider.createOffer(input)
+      return { data }
+    } catch (err) {
+      throwServiceError(err)
+    }
+  },
+
   async sendInquiryReply(
     inquiryId: string,
     payload: InquiryReplyPayload,
   ): Promise<ItemResponse<Inquiry>> {
     try {
       const data = await provider.addMessage(inquiryId, {
-        senderType: 'supply_user',
-        senderName: 'Wincasa AG',
+        senderType: payload.senderType ?? 'supply_user',
+        senderName: payload.senderName ?? 'Wincasa AG',
         subject: payload.subject,
         body: payload.body,
         attachments: payload.attachments ?? [],
@@ -58,9 +78,9 @@ export const inquiryService = {
     }
   },
 
-  async getUnreadCount(): Promise<ItemResponse<number>> {
+  async getUnreadCount(filters?: InquiryFilters): Promise<ItemResponse<number>> {
     try {
-      const data = await provider.getUnreadCount()
+      const data = await provider.getUnreadCount(filters)
       return { data }
     } catch (err) {
       throwServiceError(err)