refactor(App, navigation): migrate to Expo Router and clean up navigation structure

- Updated App entry point to utilize Expo Router, simplifying the navigation setup.
- Removed legacy navigation components and services to streamline the codebase.
- Adjusted package.json to reflect the new entry point and updated dependencies for compatibility.
- Enhanced overall application structure by consolidating navigation logic and improving maintainability.

src/components/common/AppBackButton.tsx

@@ -0,0 +1,54 @@
+import React from 'react';
+import { TouchableOpacity, StyleProp, ViewStyle, StyleSheet } from 'react-native';
+import { MaterialCommunityIcons } from '@expo/vector-icons';
+
+import { borderRadius, colors, spacing } from '../../theme';
+
+type AppBackButtonIcon = 'arrow-left' | 'close';
+
+interface AppBackButtonProps {
+  onPress: () => void;
+  icon?: AppBackButtonIcon;
+  style?: StyleProp<ViewStyle>;
+  iconColor?: string;
+  backgroundColor?: string;
+  hitSlop?: number;
+  testID?: string;
+}
+
+const AppBackButton: React.FC<AppBackButtonProps> = ({
+  onPress,
+  icon = 'arrow-left',
+  style,
+  iconColor = colors.text.primary,
+  backgroundColor = colors.background.paper,
+  hitSlop = 8,
+  testID,
+}) => {
+  return (
+    <TouchableOpacity
+      onPress={onPress}
+      style={[styles.button, { backgroundColor }, style]}
+      activeOpacity={0.75}
+      hitSlop={hitSlop}
+      testID={testID}
+      accessibilityRole="button"
+      accessibilityLabel={icon === 'close' ? '关闭' : '返回'}
+    >
+      <MaterialCommunityIcons name={icon} size={22} color={iconColor} />
+    </TouchableOpacity>
+  );
+};
+
+const styles = StyleSheet.create({
+  button: {
+    width: 36,
+    height: 36,
+    borderRadius: borderRadius.full,
+    alignItems: 'center',
+    justifyContent: 'center',
+    marginLeft: spacing.xs,
+  },
+});
+
+export default AppBackButton;