feat(demand): market rent estimate (asking vs. fair) + pre-market expected price

- lib/rentEstimate: deterministic market estimate from Standort-Intelligence (median rent benchmark + vacancy/trend) → fair rent, verdict BELOW/AT/ABOVE, deltaPct, rationale; suggestFutureRent indexes today's price by city rent trend
- MarketPricePanel in MatchDetail: asking vs. fair market rent + verdict badge + rationale; shows pre-market expected price (heute → erwartet)
- unit.expectedRentPerSqm: future pre-market price; scorer prefers it over current rent for FUTURE_AVAILABILITY
- UnitStructurePanel editor: expected-price field (with indexed suggestion) shown for pre-market-released units
- tests: rentEstimate verdict thresholds + future-rent indexing

Note: rent estimate is a deterministic market-data calc (not an LLM) — honest & testable; can be routed through IAIService later if a real model is wanted.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/lib/__tests__/rentEstimate.test.ts

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+import { describe, it, expect } from 'vitest'
+import { estimateMarketRent, suggestFutureRent } from '../rentEstimate'
+
+describe('estimateMarketRent', () => {
+  it('flags asking rent clearly above the city median as ABOVE', () => {
+    // Zürich OFFICE median = 42
+    const est = estimateMarketRent('Zürich', 'OFFICE', 60)
+    expect(est).not.toBeNull()
+    expect(est!.verdict).toBe('ABOVE')
+    expect(est!.deltaPct).toBeGreaterThan(5)
+    expect(est!.fairRentPerSqm).toBe(42)
+  })
+
+  it('flags asking rent clearly below median as BELOW', () => {
+    const est = estimateMarketRent('Zürich', 'OFFICE', 30)
+    expect(est!.verdict).toBe('BELOW')
+    expect(est!.deltaPct).toBeLessThan(-5)
+  })
+
+  it('treats near-median asking rent as AT (within ±5%)', () => {
+    const est = estimateMarketRent('Zürich', 'OFFICE', 43)
+    expect(est!.verdict).toBe('AT')
+  })
+
+  it('returns null for unknown city', () => {
+    expect(estimateMarketRent('Atlantis', 'OFFICE', 40)).toBeNull()
+  })
+
+  it('suggestFutureRent indexes by the city rent trend', () => {
+    // Zürich rentTrend12m = +4.2% → 100 * 1.042 = 104 (rounded)
+    expect(suggestFutureRent('Zürich', 100)).toBe(104)
+  })
+})

src/lib/rentEstimate.ts

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+import { getMarketRent, getCityIntelligence } from './locationIntelligence'
+
+export type RentVerdict = 'BELOW' | 'AT' | 'ABOVE'
+
+export interface RentEstimate {
+  fairRentPerSqm: number      // Median-Marktmiete als faire Benchmark
+  askingRentPerSqm: number
+  verdict: RentVerdict        // Angebot vs. Markt
+  deltaPct: number            // +über / −unter Markt (gerundet)
+  rationale: string
+  confidence: 'LOW' | 'MEDIUM' | 'HIGH'
+}
+
+/**
+ * Markt-Einschätzung der Angebotsmiete: Vergleich gegen die Median-Marktmiete
+ * (aus Standort-Intelligence) plus Leerstand/Miettrend als Kontext. Deterministisch.
+ */
+export function estimateMarketRent(city: string, assetType: string, askingRentPerSqm: number): RentEstimate | null {
+  const market = getMarketRent(city, assetType)
+  const intel = getCityIntelligence(city)
+  if (market == null || !intel || askingRentPerSqm <= 0) return null
+
+  const fair = market
+  const deltaPct = Math.round(((askingRentPerSqm - fair) / fair) * 100)
+  const verdict: RentVerdict = deltaPct > 5 ? 'ABOVE' : deltaPct < -5 ? 'BELOW' : 'AT'
+  const trendNote = `Miettrend ${intel.rentTrend12m >= 0 ? '+' : ''}${intel.rentTrend12m}% (12 M)`
+  const verdictText =
+    verdict === 'ABOVE' ? `Angebot ${deltaPct}% über Marktmedian.`
+    : verdict === 'BELOW' ? `Angebot ${Math.abs(deltaPct)}% unter Marktmedian.`
+    : 'Angebot marktkonform.'
+  const rationale = `Median ${city}: CHF ${fair}/m² · Leerstand ${intel.vacancyRatePct}% · ${trendNote}. ${verdictText}`
+  const confidence = intel.demandStrength === 'LOW' ? 'LOW' : intel.avgDaysOnMarket > 70 ? 'MEDIUM' : 'HIGH'
+
+  return { fairRentPerSqm: fair, askingRentPerSqm, verdict, deltaPct, rationale, confidence }
+}
+
+/** Indexierter Vorschlag für den künftigen Preis (Pre-Market): Heutepreis × (1 + Miettrend). */
+export function suggestFutureRent(city: string, currentRentPerSqm: number): number | null {
+  const intel = getCityIntelligence(city)
+  if (!intel || currentRentPerSqm <= 0) return null
+  return Math.round(currentRentPerSqm * (1 + intel.rentTrend12m / 100))
+}