feat(pitch): showcase mode — per-investor toggle hides financial/investor slides for customer demos

Adds is_showcase boolean to pitch_investors; when set, filters out financials,
the ask, cap table, assumptions, finanzplan, risks, and intro-presenter slides.
Slide navigation is fully dynamic — progress bar and counts update accordingly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

pitch-deck/lib/slide-order.ts

@@ -1,5 +1,17 @@
 import { SlideId } from './types'
 
+// Slides hidden in showcase (customer) mode — financial and investor-specific content
+export const SHOWCASE_HIDDEN_SLIDES = new Set<SlideId>([
+  'intro-presenter',
+  'executive-summary',
+  'financials',
+  'the-ask',
+  'cap-table',
+  'annex-assumptions',
+  'annex-finanzplan',
+  'risks',
+])
+
 export const SLIDE_ORDER: SlideId[] = [
   'intro-presenter',
   'executive-summary',