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/lib/constants.ts

@@ -139,3 +139,6 @@ export const FIT_OUT_COST_CHF_PER_SQM: Record<string, { min: number; max: number
   FULL:    { min: 50,  max: 200 },
   PREMIUM: { min: 0,   max: 50 },
 }
+
+// Assumed amortization period for fit-out investment — change here to affect all cost calculations
+export const FITOUT_AMORTIZATION_YEARS = 5