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/presenter/tts-client.ts

@@ -0,0 +1,20 @@
+import { Language } from '../types'
+
+/**
+ * TTS Stub — prepared for future Piper TTS integration via compliance-tts-service (:8095)
+ * POST /synthesize { text, voice: 'de_DE-thorsten-high' }
+ * Returns audio URL from MinIO
+ */
+export async function synthesizeSpeech(text: string, lang: Language): Promise<string | null> {
+  // TODO: Connect to compliance-tts-service
+  // const voice = lang === 'de' ? 'de_DE-thorsten-high' : 'en_US-lessac-high'
+  // const res = await fetch('http://compliance-tts-service:8095/synthesize', {
+  //   method: 'POST',
+  //   headers: { 'Content-Type': 'application/json' },
+  //   body: JSON.stringify({ text, voice }),
+  // })
+  // if (!res.ok) return null
+  // const data = await res.json()
+  // return data.audio_url
+  return null
+}