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/components/ChatFAB.tsx

@@ -5,6 +5,9 @@ import { motion, AnimatePresence } from 'framer-motion'
 import { X, Send, Bot, User, Sparkles, Maximize2, Minimize2, ArrowRight } from 'lucide-react'
 import { ChatMessage, Language, SlideId } from '@/lib/types'
 import { t } from '@/lib/i18n'
+import { SLIDE_ORDER } from '@/lib/hooks/useSlideNavigation'
+import { PresenterState } from '@/lib/presenter/types'
+import { matchFAQ, getFAQAnswer } from '@/lib/presenter/faq-matcher'
 
 interface ChatFABProps {
   lang: Language
@@ -12,6 +15,8 @@ interface ChatFABProps {
   currentIndex: number
   visitedSlides: Set<number>
   onGoToSlide: (index: number) => void
+  presenterState?: PresenterState
+  onPresenterInterrupt?: () => void
 }
 
 interface ParsedMessage {
@@ -62,18 +67,31 @@ function parseAgentResponse(content: string, lang: Language): ParsedMessage {
     }
   }
 
-  // Parse GOTO markers from the text
-  const gotoRegex = /\[GOTO:(\d+)\]/g
+  // Parse GOTO markers — support both [GOTO:N] (numeric) and [GOTO:slide-id] (string)
+  const gotoRegex = /\[GOTO:([\w-]+)\]/g
   let gotoMatch
   while ((gotoMatch = gotoRegex.exec(text)) !== null) {
-    const slideIndex = parseInt(gotoMatch[1])
-    gotos.push({
-      index: slideIndex,
-      label: lang === 'de' ? `Zu Slide ${slideIndex + 1} springen` : `Jump to slide ${slideIndex + 1}`,
-    })
+    const target = gotoMatch[1]
+    let slideIndex: number
+
+    // Try numeric index first
+    const numericIndex = parseInt(target)
+    if (!isNaN(numericIndex) && numericIndex >= 0 && numericIndex < SLIDE_ORDER.length) {
+      slideIndex = numericIndex
+    } else {
+      // Try slide ID lookup
+      slideIndex = SLIDE_ORDER.indexOf(target as SlideId)
+    }
+
+    if (slideIndex >= 0) {
+      gotos.push({
+        index: slideIndex,
+        label: lang === 'de' ? `Zu Slide ${slideIndex + 1} springen` : `Jump to slide ${slideIndex + 1}`,
+      })
+    }
   }
   // Remove GOTO markers from visible text
-  text = text.replace(/\s*\[GOTO:\d+\]/g, '')
+  text = text.replace(/\s*\[GOTO:[\w-]+\]/g, '')
 
   // Clean up trailing reminder instruction that might leak through
   text = text.replace(/\n*\(Erinnerung:.*?\)\s*$/s, '').trim()
@@ -81,7 +99,15 @@ function parseAgentResponse(content: string, lang: Language): ParsedMessage {
   return { text: text.trim(), followUps, gotos }
 }
 
-export default function ChatFAB({ lang, currentSlide, currentIndex, visitedSlides, onGoToSlide }: ChatFABProps) {
+export default function ChatFAB({
+  lang,
+  currentSlide,
+  currentIndex,
+  visitedSlides,
+  onGoToSlide,
+  presenterState = 'idle',
+  onPresenterInterrupt,
+}: ChatFABProps) {
   const i = t(lang)
   const [isOpen, setIsOpen] = useState(false)
   const [isExpanded, setIsExpanded] = useState(false)
@@ -124,28 +150,43 @@ export default function ChatFAB({ lang, currentSlide, currentIndex, visitedSlide
     const message = text || input.trim()
     if (!message || isStreaming) return
 
+    // Interrupt presenter if it's running
+    if (presenterState === 'presenting' && onPresenterInterrupt) {
+      onPresenterInterrupt()
+    }
+
     setInput('')
     setMessages(prev => [...prev, { role: 'user', content: message }])
     setIsStreaming(true)
     setIsWaiting(true)
 
+    // Check FAQ first for instant response
+    const faqMatch = matchFAQ(message, lang)
+
     abortRef.current = new AbortController()
 
     try {
+      const requestBody: Record<string, unknown> = {
+        message,
+        history: messages.slice(-10),
+        lang,
+        slideContext: {
+          currentSlide,
+          currentIndex,
+          visitedSlides: Array.from(visitedSlides),
+          totalSlides: SLIDE_ORDER.length,
+        },
+      }
+
+      // If FAQ matched, send the cached answer for fast streaming (no LLM call)
+      if (faqMatch) {
+        requestBody.faqAnswer = getFAQAnswer(faqMatch, lang)
+      }
+
       const res = await fetch('/api/chat', {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({
-          message,
-          history: messages.slice(-10),
-          lang,
-          slideContext: {
-            currentSlide,
-            currentIndex,
-            visitedSlides: Array.from(visitedSlides),
-            totalSlides: 13,
-          },
-        }),
+        body: JSON.stringify(requestBody),
         signal: abortRef.current.signal,
       })
 
@@ -175,6 +216,20 @@ export default function ChatFAB({ lang, currentSlide, currentIndex, visitedSlide
           })
         }
       }
+
+      // If FAQ matched and has a goto_slide, add a GOTO marker to the response
+      if (faqMatch?.goto_slide) {
+        const gotoIdx = SLIDE_ORDER.indexOf(faqMatch.goto_slide)
+        if (gotoIdx >= 0) {
+          const suffix = `\n\n[GOTO:${faqMatch.goto_slide}]`
+          content += suffix
+          setMessages(prev => {
+            const updated = [...prev]
+            updated[updated.length - 1] = { role: 'assistant', content }
+            return updated
+          })
+        }
+      }
     } catch (err: unknown) {
       if (err instanceof Error && err.name === 'AbortError') return
       console.error('Chat error:', err)
@@ -277,6 +332,10 @@ export default function ChatFAB({ lang, currentSlide, currentIndex, visitedSlide
               <circle cx="12" cy="10" r="1" fill="currentColor" />
               <circle cx="15" cy="10" r="1" fill="currentColor" />
             </svg>
+            {/* Presenter active indicator */}
+            {presenterState !== 'idle' && (
+              <span className="absolute -top-1 -right-1 w-3 h-3 rounded-full bg-green-400 border-2 border-black animate-pulse" />
+            )}
           </motion.button>
         )}
       </AnimatePresence>
@@ -307,7 +366,9 @@ export default function ChatFAB({ lang, currentSlide, currentIndex, visitedSlide
                   <span className="text-xs text-white/30 ml-2">
                     {isStreaming
                       ? (lang === 'de' ? 'antwortet...' : 'responding...')
-                      : (lang === 'de' ? 'online' : 'online')
+                      : presenterState !== 'idle'
+                        ? (lang === 'de' ? 'Presenter aktiv' : 'Presenter active')
+                        : (lang === 'de' ? 'online' : 'online')
                     }
                   </span>
                 </div>