refactor: extract reusable library

- move reusable domain, data, state, ui code into src/lib
- update host screens to consume new library exports
- document architecture and configure path aliases
- bump astro integration dependencies for compatibility

Refs #30

src/components/App.tsx

@@ -1,20 +1,24 @@
 import { h } from 'preact';
 import { useEffect, useCallback } from 'preact/hooks';
 
-import { useGameState } from '../hooks/useGameState';
-import { useNavigation, useNewGameWizard } from '../hooks/useNavigation';
-import { useModal, useValidationModal, useCompletionModal } from '../hooks/useModal';
+import {
+  useGameState,
+  useNavigation,
+  useNewGameWizard,
+  useModal,
+  useValidationModal,
+  useCompletionModal,
+} from '@lib/state';
+import { GameService } from '@lib/data/gameService';
+import type { StandardGame, Game, EndlosGame } from '@lib/domain/types';
 
-import { GameService } from '../services/gameService';
-import type { StandardGame, Game, EndlosGame } from '../types/game';
-
-import { Layout } from './ui/Layout';
+import { Layout } from '@lib/ui/Layout';
 import GameListScreen from './screens/GameListScreen';
 import NewGameScreen from './screens/NewGameScreen';
 import GameDetailScreen from './screens/GameDetailScreen';
-import Modal from './Modal';
-import ValidationModal from './ValidationModal';
-import GameCompletionModal from './GameCompletionModal';
+import Modal from '@lib/ui/Modal';
+import ValidationModal from '@lib/ui/ValidationModal';
+import GameCompletionModal from '@lib/features/game-lifecycle/GameCompletionModal';
 import FullscreenToggle from './FullscreenToggle';
 
 /**