fix: clear stale search criteria on text edit, fix Zürich false-positive, improve cost breakdown and fit-out labels

- AISearch: clear parsed criteria when user manually edits text input so stale locations (e.g. Zürich) no longer persist after retyping
- needParser: fix ZURICH_SIGNALS substring bug — "kreis N" now uses word-boundary regex so "umkreis 22" no longer matches "kreis 2"
- CompareTableBody: row 9 shows full cost breakdown (Miete + NK + amortised fit-out) using FITOUT_AMORTIZATION_YEARS from constants
- FitOutCostPanel: replace local AMORTIZATION_YEARS with FITOUT_AMORTIZATION_YEARS from constants.ts (single source of truth)
- constants.ts: add FITOUT_AMORTIZATION_YEARS = 5 — change here to affect all cost calculations
- PropertyIntelligenceCard: translate raw fitOut enum to German labels (Rohbau/Grundausbau/Vollausbau/Premium-Ausbau) with explanatory tooltips; add tooltip on contract duration chip

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

src/pages/demand/AISearch.tsx

@@ -56,6 +56,9 @@ export default function AISearch() {
     isManualTextRef.current = text !== ''
     setIsAutoGen(false)
     setInputText(text)
+    // Clear stale parse results when user edits the text manually
+    setCriteria({})
+    setParseResult(null)
   }
 
   function handleAiAutofill() {