feat(pitch-deck): add AI Presenter mode with LiteLLM migration and FAQ system

- Migrate chat API from Ollama to LiteLLM (OpenAI-compatible SSE)
- Add 15-min presenter storyline with bilingual scripts for all 20 slides
- Add FAQ system (30 entries) with keyword matching for instant answers
- Add IntroPresenterSlide with avatar placeholder and start button
- Add PresenterOverlay (progress bar, subtitle text, play/pause/stop)
- Add AvatarPlaceholder with pulse animation during speaking
- Add usePresenterMode hook (state machine: idle→presenting→paused→answering→resuming)
- Add 'P' keyboard shortcut to toggle presenter mode
- Support [GOTO:slide-id] markers in chat responses
- Dynamic slide count (was hardcoded 13, now from SLIDE_ORDER)
- TTS stub prepared for future Piper integration

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

pitch-deck/lib/hooks/useKeyboard.ts

@@ -11,6 +11,7 @@ interface UseKeyboardProps {
   onFullscreen: () => void
   onLanguageToggle: () => void
   onMenuToggle: () => void
+  onPresenterToggle?: () => void
   onGoToSlide: (index: number) => void
   enabled?: boolean
 }
@@ -24,6 +25,7 @@ export function useKeyboard({
   onFullscreen,
   onLanguageToggle,
   onMenuToggle,
+  onPresenterToggle,
   onGoToSlide,
   enabled = true,
 }: UseKeyboardProps) {
@@ -74,6 +76,11 @@ export function useKeyboard({
           e.preventDefault()
           onMenuToggle()
           break
+        case 'p':
+        case 'P':
+          e.preventDefault()
+          onPresenterToggle?.()
+          break
         case '1':
         case '2':
         case '3':
@@ -88,7 +95,7 @@ export function useKeyboard({
           break
       }
     },
-    [enabled, onNext, onPrev, onFirst, onLast, onOverview, onFullscreen, onLanguageToggle, onMenuToggle, onGoToSlide]
+    [enabled, onNext, onPrev, onFirst, onLast, onOverview, onFullscreen, onLanguageToggle, onMenuToggle, onPresenterToggle, onGoToSlide]
   )
 
   useEffect(() => {