feat: all 4 UX priorities — wizard, examples, onboarding, pipeline

- Offer wizard: 4→3 steps by merging 'Prüfen' into PDF review step
- Search mask: quick-select chips for area ranges, budget, and city presets
- Onboarding: WelcomeDialog (3 slides, localStorage) on first visit
- Deal Pipeline: Kanban board (6 stages, 8 mock items, advance-to-next-stage)
  added to demand workspace navigation

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

src/components/anfragencenter/OfferWizard.tsx

@@ -16,13 +16,20 @@ import { OfferPdfReviewStep } from './OfferPdfReviewStep'
 import { OfferCheckedAction } from './OfferCheckedAction'
 import { OfferChatComposer } from './OfferChatComposer'
 
+// 'checked' is internal — merged into pdf_review step; only 3 steps shown
 const STEPS: { key: OfferStep; label: string }[] = [
   { key: 'select_properties', label: 'Objekte wählen' },
-  { key: 'pdf_review', label: 'PDF-Vorschau' },
-  { key: 'checked', label: 'Prüfen' },
-  { key: 'send', label: 'Senden' },
+  { key: 'pdf_review',        label: 'Vorschau & Prüfen' },
+  { key: 'send',              label: 'Senden' },
 ]
 
+const STEP_DISPLAY_INDEX: Record<OfferStep, number> = {
+  select_properties: 0,
+  pdf_review: 1,
+  checked: 1, // same visual step as pdf_review
+  send: 2,
+}
+
 export function OfferWizard() {
   const theme = useTheme()
   const fullScreen = useMediaQuery(theme.breakpoints.down('md'))
@@ -32,7 +39,7 @@ export function OfferWizard() {
   const currentStep = useOfferWizardStore(s => s.currentStep)
   const needTitle = useOfferWizardStore(s => s.needTitle)
 
-  const activeIndex = STEPS.findIndex(s => s.key === currentStep)
+  const activeIndex = STEP_DISPLAY_INDEX[currentStep] ?? 0
 
   return (
     <Dialog