refactor(arch): eliminate direct service calls in components — route all through hooks

New hook files:
- useAuth.ts: useLogin, useSwitchDemoRole, useSwitchOrganization
- useAI.ts: useParseNeed, useGenerateOfferEmail, useGenerateDecisionBrief, useParseListingText
- useAssistant.ts: useAssistantSuggestions (useQuery), useAssistantAnswer (useMutation)
- useOfferReport.ts: useOfferReportByInquiry, useCreateOfferReport, useUpdateOfferReport, useGenerateOfferReportPdf
- useInquiryReport.ts: useInquiryReportByInquiry, useCreateInquiryReport, useUpdateInquiryReport, useFinalizeInquiryReport
- useMarketReport.ts: useMarketReport
- useWeighting.ts: useDefaultWeights (synchronous wrapper)
- useUnitMatches.ts: useUnitMatchesMap, useUnitBundle, useBundleMatches (useMemo wrappers)

Extended hooks: useProperties (add update/create/remove mutations),
useNeeds (add useCreateNeed), useMatches (add useNeedMatchesForProperty,
useAdditionalMatchesForInquiry), useReviewQueue (add useCreateReviewTask)

Updated 21 components/pages: all direct service imports replaced with hooks.
Deliberate exception: getRecommendedActions in DataQuality.tsx (pure sync utility, no provider access).

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

src/pages/auth/LoginScreen.tsx

@@ -1,5 +1,5 @@
 import { useState } from 'react'
-import { useNavigate, Navigate } from 'react-router'
+import { Navigate } from 'react-router'
 import {
   Box,
   Button,
@@ -12,7 +12,7 @@ import {
   Typography,
 } from '@mui/material'
 import { Building2 } from 'lucide-react'
-import { authService } from '../../services/authService'
+import { useLogin, useSwitchDemoRole } from '../../hooks/useAuth'
 import { useSessionStore } from '../../stores/sessionStore'
 import { UserRole } from '../../domain/enums'
 
@@ -23,42 +23,37 @@ const DEMO_ROLES: { role: UserRole; label: string; description: string }[] = [
 
 export default function LoginScreen() {
   const { isAuthenticated } = useSessionStore()
-  const navigate = useNavigate()
+  const loginMutation = useLogin()
+  const switchDemoRoleMutation = useSwitchDemoRole()
   const [email, setEmail] = useState('admin@ideal-sharing.ch')
   const [password, setPassword] = useState('')
-  const [loading, setLoading] = useState(false)
   const [error, setError] = useState<string | null>(null)
 
   if (isAuthenticated) {
     return <Navigate to="/" replace />
   }
 
-  async function handleLogin(e: React.FormEvent) {
+  const loading = loginMutation.isPending || switchDemoRoleMutation.isPending
+
+  function handleLogin(e: React.FormEvent) {
     e.preventDefault()
     if (!email) {
       setError('Bitte E-Mail-Adresse eingeben.')
       return
     }
-    setLoading(true)
     setError(null)
-    try {
-      await authService.login(email, password)
-      navigate('/')
-    } catch {
-      setError('Anmeldung fehlgeschlagen. Bitte erneut versuchen.')
-    } finally {
-      setLoading(false)
-    }
+    loginMutation.mutate(
+      { email, password },
+      {
+        onError: () => {
+          setError('Anmeldung fehlgeschlagen. Bitte erneut versuchen.')
+        },
+      },
+    )
   }
 
-  async function handleDemoLogin(role: UserRole) {
-    setLoading(true)
-    try {
-      await authService.switchDemoRole(role)
-      navigate('/')
-    } finally {
-      setLoading(false)
-    }
+  function handleDemoLogin(role: UserRole) {
+    switchDemoRoleMutation.mutate(role)
   }
 
   return (