chore: remove unused Expo template files and dependencies, add CI workflow

- 17 files unreferenced by the app (knip): hello-wave, parallax-scroll-view, themed-*, icon-symbol, Button, GlassCard, ScreenWrapper, Models catalog, duplicated theme/color-scheme hooks
- scripts/reset-project.js and its npm script: it moves app/ to app-example and would wipe the project
- dependencies only used by those files: expo-image, expo-symbols, expo-web-browser, react-native-sse, @babel/plugin-transform-runtime
- GitHub Actions workflow running typecheck, lint, tests and the web export

components/chat/EmptyState.tsx

@@ -3,7 +3,7 @@ import { MessageSquare, Sparkles } from 'lucide-react-native';
 import React from 'react';
 import { StyleSheet, Text, TouchableOpacity, View } from 'react-native';
 
-export const PROMPT_SUGGESTIONS = [
+const PROMPT_SUGGESTIONS = [
     'Explain recursion in simple terms',
     'Write a short poem about coding',
     'What are the best practices for React Native?',