feat: add mobile application structure with emotion picker and API integration

- Added favicon and icon assets for the mobile app.
- Implemented EmotionPicker component for selecting emotions with child options.
- Created hooks for fetching emotions, feeds, and rapport data.
- Established API service for handling requests and authentication.
- Integrated Zustand for state management of user authentication.
- Defined color palette for the application.
- Set up TypeScript types for various entities including User, Emotion, and Feed.
- Configured Babel and TypeScript for the mobile project.
- Added package.json with necessary dependencies for Expo and React Native.

mobile/lib/api.ts

@@ -0,0 +1,37 @@
+import axios from 'axios';
+import * as SecureStore from 'expo-secure-store';
+import { Platform } from 'react-native';
+
+const API_URL = Platform.select({
+  android: 'http://10.0.2.2:8000/api/v1',
+  ios: 'http://localhost:8000/api/v1',
+  default: 'http://localhost:8000/api/v1',
+});
+
+const api = axios.create({
+  baseURL: API_URL,
+  headers: {
+    'Content-Type': 'application/json',
+    Accept: 'application/json',
+  },
+});
+
+api.interceptors.request.use(async (config) => {
+  const token = await SecureStore.getItemAsync('cesizen_token');
+  if (token) {
+    config.headers.Authorization = `Bearer ${token}`;
+  }
+  return config;
+});
+
+api.interceptors.response.use(
+  (response) => response,
+  async (error) => {
+    if (error.response?.status === 401) {
+      await SecureStore.deleteItemAsync('cesizen_token');
+    }
+    return Promise.reject(error);
+  }
+);
+
+export default api;