feat: Phase 5+6 — Finanzplan Bridge + Financials-Slide Sync

- Adapter: fp_* Tabellen → FMResult Interface (60 Monate)
- Compute-Endpoint: source=finanzplan delegiert an Finanzplan-Engine
- useFinancialModel Hook: computeFromFinanzplan() + finanzplanResults
- FinancialsSlide: Toggle "Szenario-Modell" vs "Finanzplan (Excel)"
- Gruendungsdatum fix: EK+FK auf Aug (m8), Raumkosten ab Aug
- Startup-Preisstaffel: <10 MA ab 3.600 EUR/Jahr, 14-Tage-Test

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pitch-deck/lib/hooks/useFinancialModel.ts

@@ -41,17 +41,17 @@ export function useFinancialModel() {
     }
   }, [activeScenarioId]) // eslint-disable-line react-hooks/exhaustive-deps
 
-  const compute = useCallback(async (scenarioId: string) => {
+  const compute = useCallback(async (scenarioId: string, source?: string) => {
     setComputing(true)
     try {
       const res = await fetch('/api/financial-model/compute', {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({ scenarioId }),
+        body: JSON.stringify({ scenarioId, source }),
       })
       if (res.ok) {
         const data: FMComputeResponse = await res.json()
-        setResults(prev => new Map(prev).set(scenarioId, data))
+        setResults(prev => new Map(prev).set(source === 'finanzplan' ? 'finanzplan' : scenarioId, data))
       }
     } catch (err) {
       console.error('Compute failed:', err)
@@ -60,6 +60,10 @@ export function useFinancialModel() {
     }
   }, [])
 
+  const computeFromFinanzplan = useCallback(async () => {
+    await compute('', 'finanzplan')
+  }, [compute])
+
   const updateAssumption = useCallback(async (scenarioId: string, key: string, value: number | number[]) => {
     // Optimistic update in local state
     setScenarios(prev => prev.map(s => {
@@ -90,6 +94,7 @@ export function useFinancialModel() {
 
   const activeScenario = scenarios.find(s => s.id === activeScenarioId) || null
   const activeResults = activeScenarioId ? results.get(activeScenarioId) || null : null
+  const finanzplanResults = results.get('finanzplan') || null
 
   return {
     scenarios,
@@ -97,6 +102,7 @@ export function useFinancialModel() {
     activeScenarioId,
     setActiveScenarioId,
     activeResults,
+    finanzplanResults,
     results,
     loading,
     computing,
@@ -104,6 +110,7 @@ export function useFinancialModel() {
     setCompareMode,
     compute,
     computeAll,
+    computeFromFinanzplan,
     updateAssumption,
   }
 }