FRE-623: Build KPI dashboard with Mixpanel, GA4, Stripe panels and unified report

- Created KPIDashboard component with tab navigation (product/acquisition/revenue/report)
- Created MixpanelPanel for product KPIs linking to Mixpanel
- Created GA4Panel for acquisition KPIs linking to GA4
- Created StripePanel for revenue KPIs linking to Stripe dashboard
- Created UnifiedReport with KPI thresholds table and reporting schedule
- Added KPI dashboard route (/app/kpi) and sidebar navigation link
- Added KPI dashboard CSS styles (metric cards, tabs, table, info cards)
- Fixed pre-existing parse errors in Faq.tsx (unescaped apostrophes)
- Fixed pre-existing CSS import paths in routes.tsx

Co-Authored-By: Paperclip <noreply@paperclip.ing>

src/components/layout/AppLayout.tsx

@@ -25,6 +25,10 @@ export const AppLayout: Component<any> = (props) => {
             <span class="freno-nav-icon">📊</span>
             <span class="freno-nav-text">Dashboard</span>
           </A>
+          <A href="/kpi" class="freno-nav-link">
+            <span class="freno-nav-icon">📈</span>
+            <span class="freno-nav-text">KPIs</span>
+          </A>
           <A href="/projects" class="freno-nav-link">
             <span class="freno-nav-icon">📁</span>
             <span class="freno-nav-text">Projects</span>
@@ -79,6 +83,7 @@ function getPageTitle(): string {
   const path = window.location.pathname;
   const titles: Record<string, string> = {
     '/dashboard': 'Dashboard',
+    '/kpi': 'KPI Dashboard',
     '/projects': 'Projects',
     '/projects/new': 'New Project',
     '/profile': 'Profile',