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/components/anfragencenter/ActiveInquiriesTab.tsx

@@ -2,6 +2,7 @@ import { useEffect, useState } from 'react'
 import { Box, IconButton, Tooltip, Typography, useMediaQuery, useTheme } from '@mui/material'
 import { ArrowLeft, LayoutGrid, List as ListIcon, Inbox } from 'lucide-react'
 import { useActiveInquiries } from '../../hooks/useInquiries'
+import type { InquiryFilters } from '../../provider/IInquiryProvider'
 import { EmptyState } from '../ui'
 import { InquiryList } from './InquiryList'
 import { InquiryCardGrid } from './InquiryCardGrid'
@@ -17,8 +18,14 @@ function loadViewMode(): ViewMode {
   return stored === 'grid' ? 'grid' : 'list'
 }
 
-export function ActiveInquiriesTab() {
-  const { data: inquiries = [], isLoading } = useActiveInquiries()
+interface Props {
+  filters?: InquiryFilters
+  emptyTitle?: string
+  emptyDescription?: string
+}
+
+export function ActiveInquiriesTab({ filters, emptyTitle, emptyDescription }: Props = {}) {
+  const { data: inquiries = [], isLoading } = useActiveInquiries(filters)
   const [selectedId, setSelectedId] = useState<string | null>(null)
   const [view, setView] = useState<ViewMode>(loadViewMode())
   const theme = useTheme()
@@ -41,8 +48,8 @@ export function ActiveInquiriesTab() {
     return (
       <EmptyState
         icon={<Inbox size={40} />}
-        title="Keine aktiven Anfragen"
-        description="Sobald Interessenten Anfragen zu Ihren Objekten stellen, erscheinen diese hier."
+        title={emptyTitle ?? 'Keine aktiven Anfragen'}
+        description={emptyDescription ?? 'Sobald Interessenten Anfragen zu Ihren Objekten stellen, erscheinen diese hier.'}
       />
     )
   }

src/components/anfragencenter/OfferChatComposer.tsx

@@ -2,6 +2,9 @@ import { Box, Button, CircularProgress, IconButton, TextField, Typography } from
 import { ArrowLeft, FileText, Paperclip, Send, X } from 'lucide-react'
 import { useOfferWizardStore } from '../../stores/offerWizardStore'
 import { useSendOffer } from '../../hooks/useOffers'
+import { useCreateOffer } from '../../hooks/useInquiries'
+import { useLatentNeedById } from '../../hooks/useLatentNeeds'
+import { useSessionStore } from '../../stores/sessionStore'
 import { useToastStore } from '../../stores/toastStore'
 import { AiOfferEmailButton } from './AiOfferEmailButton'
 import { mockProperties } from '../../mock-data/properties'
@@ -24,6 +27,9 @@ export function OfferChatComposer() {
   const reset = useOfferWizardStore(s => s.reset)
 
   const sendOffer = useSendOffer()
+  const createOffer = useCreateOffer()
+  const { data: latentNeed } = useLatentNeedById(needId)
+  const currentUser = useSessionStore(s => s.currentUser)
   const showToast = useToastStore(s => s.showToast)
 
   const propertyTitles = selectedPropertyIds.map(id => {
@@ -60,6 +66,19 @@ export function OfferChatComposer() {
       showToast(`Fehler: ${res.error}`, 'error')
       return
     }
+    // Angebot als Konversation im Nachfrager-Postfach materialisieren
+    await createOffer.mutateAsync({
+      organizationId: currentUser?.organizationId ?? 'org-wincasa',
+      tenantOrgId: latentNeed?.tenantOrgId ?? 'org-mobimo',
+      needId: needId ?? '',
+      propertyId: selectedPropertyIds[0] ?? '',
+      offeredPropertyIds: selectedPropertyIds,
+      subject,
+      message: body,
+      senderName: currentUser?.organizationName ?? 'Wincasa AG',
+      recipientName: latentNeed?.tenantCompany,
+      attachments,
+    })
     showToast('Angebot erfolgreich gesendet', 'success')
     reset()
   }