feat: Finanzplan Phase 1-4 — DB + Engine + API + Spreadsheet-UI

Phase 1: DB-Schema (12 fp_* Tabellen) + Excel-Import (332 Zeilen importiert)
Phase 2: Compute Engine (Personal, Invest, Umsatz, Material, Betrieblich, Liquiditaet, GuV)
Phase 3: API (/api/finanzplan/ — GET sheets, PUT cells, POST compute)
Phase 4: Spreadsheet-UI (FinanzplanSlide als Annex mit Tab-Leiste, editierbarem Grid, Jahres-Navigation)

Zusaetzlich:
- Gruendungsdatum verschoben: Feb→Aug 2026 (DB + Personalkosten)
- Neue Preisstaffel: Startup/<10 MA ab 3.600 EUR/Jahr (14-Tage-Test, Kreditkarte)
- Competition-Slide: Pricing-Tiers aktualisiert

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

pitch-deck/components/slides/CompetitionSlide.tsx

@@ -280,7 +280,8 @@ const PRICING_COMPARISON: CompetitorPricing[] = [
     model: 'Cloud (BSI DE / OVH FR)',
     publicPricing: true,
     tiers: [
-      { name: { de: '<50 MA', en: '<50 emp.' }, price: 'ab €1.250/mo', annual: 'ab €15.000/yr', notes: { de: 'Cloud, modular, 84 Regularien', en: 'Cloud, modular, 84 regulations' } },
+      { name: { de: 'Startup/<10', en: 'Startup/<10' }, price: 'ab €300/mo', annual: 'ab €3.600/yr', notes: { de: '14-Tage-Test, Kreditkarte', en: '14-day trial, credit card' } },
+      { name: { de: '10-50 MA', en: '10-50 emp.' }, price: 'ab €1.250/mo', annual: 'ab €15.000/yr', notes: { de: 'Cloud, modular, 84 Regularien', en: 'Cloud, modular, 84 regulations' } },
       { name: { de: '50-250 MA', en: '50-250 emp.' }, price: 'ab €2.500/mo', annual: 'ab €30.000/yr', notes: { de: 'Cloud, alle Module, Priority', en: 'Cloud, all modules, priority' } },
       { name: { de: '250+ MA', en: '250+ emp.' }, price: 'ab €3.500/mo', annual: 'ab €40.000/yr', notes: { de: 'Cloud, Enterprise, Dedicated', en: 'Cloud, enterprise, dedicated' } },
     ],