feat(pitch-deck): USP slide redesign + add to sidebar

- USP added to slideNames (DE+EN) and chat display names
- Circular layout: BreakPilot hub center, rotating ring,
  Compliance & Code sections inside circle
- 4 capability cards in corners connected by dashed lines
- Removed variant toggle (kept variant A design)

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

pitch-deck/lib/i18n.ts

@@ -13,6 +13,7 @@ const translations = {
       'Cover',
       'Das Problem',
       'Die Lösung',
+      'USP',
       'Regulatorische Landschaft',
       'Modularer Baukasten',
       'So funktioniert\'s',
@@ -308,6 +309,7 @@ const translations = {
       'Cover',
       'The Problem',
       'The Solution',
+      'USP',
       'Regulatory Landscape',
       'Modular Toolkit',
       'How It Works',