refactor: unit-centric lease view — Einheiten & Mietverträge

Replace building-level Miet- & Mieterinformationen section with
unit-level lease display. Each unit row now shows tenant name and
lease end date directly; expand reveals full contract details
(Mietbeginn, Mietende, Laufzeit, Breakout, source system, doc link).

Floor grouping groups consecutive same-floor units under one label.
Domain model extended with Lease and Tenant types; deprecated
property-level tenant fields preserved via @deprecated for compat.

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

src/domain/index.ts

@@ -1,4 +1,6 @@
 export * from './enums'
+export * from './tenant'
+export * from './lease'
 export * from './property'
 export * from './need'
 export * from './match'

src/domain/lease.ts

@@ -0,0 +1,20 @@
+import type { Tenant } from './tenant'
+
+export interface Lease {
+  id: string
+  unitId: string
+  tenant: Tenant
+  rentPerSqm: number             // CHF/m²/Jahr
+  startDate: string              // ISO date
+  endDate: string                // ISO date
+  contractDurationYears?: number
+  breakoutOption?: boolean
+  breakoutOptionDate?: string
+  status: 'ACTIVE' | 'FUTURE' | 'EXPIRED'
+  sourceSystem?: 'SAP_REFX' | 'GARAIO_REM' | 'MANUAL' | string
+  sourceId?: string              // ID in source ERP
+  importedAt?: string
+  lastUpdatedAt?: string
+  contractDocumentUrl?: string
+  contractDocumentName?: string
+}

src/domain/property.ts

@@ -4,6 +4,7 @@ import type {
 } from './enums'
 import { AvailabilityStatus as AS } from './enums'
 import type { PropertyUnit } from './unit'
+import type { Lease } from './lease'
 
 // Re-export unit types so all existing imports from 'property' continue to work
 export type { PropertyUnit, UnitBundle, UnitNeedMatch } from './unit'
@@ -137,18 +138,26 @@ export interface Property {
   description?: string
   images?: string[]
   floorPlanUrl?: string
-  leaseContractUrl?: string    // link to the signed lease document
-  leaseContractName?: string   // display label, e.g. "Mietvertrag 2021–2026"
+  /** @deprecated Use unit.leases[].contractDocumentUrl instead */
+  leaseContractUrl?: string
+  /** @deprecated Use unit.leases[].contractDocumentName instead */
+  leaseContractName?: string
 
   propertyNumber?: string
   units?: PropertyUnit[]
   mapImageUrl?: string
 
+  /** @deprecated Use unit.leases instead */
   leaseTerm?: string
+  /** @deprecated Use unit.leases[].startDate instead */
   leaseStartDate?: string
+  /** @deprecated Use unit.leases[].endDate instead */
   leaseEndDate?: string
+  /** @deprecated Use unit.leases[].breakoutOption instead */
   breakoutOption?: boolean
+  /** @deprecated Use unit.leases[].breakoutOptionDate instead */
   breakoutOptionDate?: string
+  /** @deprecated Use unit.leases[].tenant.companyName instead */
   currentTenant?: string
   importedFrom?: string
   importedAt?: string
@@ -169,9 +178,29 @@ export type UpdatePropertyInput = Partial<CreatePropertyInput>
  * Returns the rentable units of a property.
  * For properties without explicit units, synthesises one unit from property-level data
  * so that all matching logic can operate uniformly at unit level.
+ * Property-level lease fields are synthesised into a proper Lease object for backward compat.
  */
 export function getEffectiveUnits(p: Property): PropertyUnit[] {
   if (p.units && p.units.length > 0) return p.units
+
+  const syntheticLease: Lease | undefined = p.currentTenant
+    ? {
+        id: `${p.id}-lease`,
+        unitId: p.id,
+        tenant: { id: `${p.id}-tenant`, companyName: p.currentTenant },
+        rentPerSqm: p.rentPricePerSqm,
+        startDate: p.leaseStartDate ?? '',
+        endDate: p.leaseEndDate ?? '',
+        contractDurationYears: p.contractDurationMonths ? Math.round(p.contractDurationMonths / 12) : undefined,
+        breakoutOption: p.breakoutOption,
+        breakoutOptionDate: p.breakoutOptionDate,
+        status: p.leaseEndDate && new Date(p.leaseEndDate) > new Date() ? 'ACTIVE' : 'EXPIRED',
+        sourceSystem: p.importedFrom ?? 'MANUAL',
+        contractDocumentUrl: p.leaseContractUrl,
+        contractDocumentName: p.leaseContractName,
+      }
+    : undefined
+
   return [{
     id: p.id,
     propertyId: p.id,
@@ -180,9 +209,7 @@ export function getEffectiveUnits(p: Property): PropertyUnit[] {
     areaSqm: p.areaSqm,
     available: p.availabilityStatus === AS.AVAILABLE_NOW || p.availabilityStatus === AS.AVAILABLE_SOON,
     rentPricePerSqm: p.rentPricePerSqm,
-    currentTenant: p.currentTenant,
-    leaseTerm: p.leaseTerm,
-    leaseEndDate: p.leaseEndDate,
+    leases: syntheticLease ? [syntheticLease] : [],
     schattenmarktRelease: p.schattenmarktRelease?.enabled
       ? { enabled: true, availableFrom: p.leaseEndDate }
       : undefined,

src/domain/tenant.ts

@@ -0,0 +1,10 @@
+export interface Tenant {
+  id: string
+  companyName: string
+  industry?: string
+  contactPerson?: {
+    name: string
+    email?: string
+    phone?: string
+  }
+}

src/domain/unit.ts

@@ -1,22 +1,30 @@
 // ── Rentable Unit — primary entity for demand-side matching ──────────────────
 //
-// A Property is the building/address container.
-// A PropertyUnit is what is actually rented: a specific floor, wing, or section.
-// Floor level is business-critical: retail needs EG for walk-in traffic,
-// offices can occupy upper floors, logistics needs ground-level loading access.
+// A Property is the building/address container (Liegenschaft).
+// A PropertyUnit is what is actually rented: a specific floor, wing, or section (Mietobjekt).
+// Floor level is an attribute of the unit — not a separate entity (matches Garaio REM / SAP RE-FX).
+// Tenant and contract data live on Lease, not directly on the unit.
+
+import type { Lease } from './lease'
+import type { AvailabilityStatus } from './enums'
+import { AvailabilityStatus as AS } from './enums'
 
 export interface PropertyUnit {
   id: string
-  propertyId?: string       // FK to parent Property
+  propertyId?: string       // FK to parent Property (Liegenschaft)
   floorLevel: number        // 0=EG, 1=1.OG, -1=UG1
   unitLabel?: string        // e.g. "Nord", "West", "Einheit A"
   areaSqm: number
   available: boolean
   rentPricePerSqm?: number  // annual CHF/m²; falls back to property.rentPricePerSqm
+  leases?: Lease[]          // Mietverträge — current, historical, future
+  /** @deprecated Use leases[].tenant.companyName */
   currentTenant?: string
-  leaseTerm?: string
+  /** @deprecated Use leases[].endDate */
   leaseEndDate?: string
-  floorPlanUrl?: string        // optional floor plan image
+  /** @deprecated Use leases[0].contractDurationYears */
+  leaseTerm?: string
+  floorPlanUrl?: string
   // Flexible letting (Teilfläche)
   isFlexible?: boolean
   minLettableSqm?: number
@@ -28,6 +36,23 @@ export interface PropertyUnit {
   }
 }
 
+// Derives availability from the unit's lease list.
+// Use this instead of reading property.availabilityStatus directly.
+export function getUnitAvailability(unit: PropertyUnit): {
+  status: AvailabilityStatus
+  availableFrom?: string
+  activeLease?: Lease
+} {
+  const active = unit.leases?.find(l => l.status === 'ACTIVE')
+  if (!active) return { status: AS.AVAILABLE_NOW }
+  const now = new Date()
+  const monthsToEnd = (new Date(active.endDate).getTime() - now.getTime()) / (1000 * 60 * 60 * 24 * 30)
+  if (monthsToEnd <= 12) {
+    return { status: AS.AVAILABLE_SOON, availableFrom: active.endDate, activeLease: active }
+  }
+  return { status: AS.OCCUPIED, activeLease: active }
+}
+
 // A bundle groups multiple free units into a combined offer
 export interface UnitBundle {
   unitIds: string[]