Add PostCSS configuration and skills lock file

- Created a new PostCSS configuration file to integrate Tailwind CSS.
- Added a skills lock file containing various Expo skills with their respective source and computed hashes.

app/_layout.tsx

@@ -1,22 +1,43 @@
-import { DarkTheme, DefaultTheme, ThemeProvider } from '@react-navigation/native';
-import { Stack } from 'expo-router';
-import { StatusBar } from 'expo-status-bar';
-import 'react-native-reanimated';
+import OpenIMSDK from "@openim/rn-client-sdk";
+import {
+  DarkTheme,
+  DefaultTheme,
+  ThemeProvider,
+} from "@react-navigation/native";
+import { Stack } from "expo-router";
+import { StatusBar } from "expo-status-bar";
+import RNFS from "react-native-fs";
+import "react-native-reanimated";
+import "../global.css";
 
-import { useColorScheme } from '@/hooks/use-color-scheme';
+import { useColorScheme } from "@/hooks/use-color-scheme";
 
 export const unstable_settings = {
-  anchor: '(tabs)',
+  anchor: "(tabs)",
 };
 
 export default function RootLayout() {
   const colorScheme = useColorScheme();
 
+  RNFS.mkdir(RNFS.DocumentDirectoryPath + "/tmp");
+
+  OpenIMSDK.initSDK({
+    apiAddr: "https://openim-api.riwsan.com/api",
+    wsAddr: "wss://openim-api.riwsan.com/msg_gateway",
+    dataDir: RNFS.DocumentDirectoryPath + "/tmp",
+    logFilePath: RNFS.DocumentDirectoryPath + "/tmp",
+    logLevel: 5,
+    isLogStandardOutput: true,
+  });
+
   return (
-    <ThemeProvider value={colorScheme === 'dark' ? DarkTheme : DefaultTheme}>
+    <ThemeProvider value={colorScheme === "dark" ? DarkTheme : DefaultTheme}>
       <Stack>
         <Stack.Screen name="(tabs)" options={{ headerShown: false }} />
-        <Stack.Screen name="modal" options={{ presentation: 'modal', title: 'Modal' }} />
+        <Stack.Screen
+          name="modal"
+          options={{ presentation: "modal", title: "Modal" }}
+        />
       </Stack>
       <StatusBar style="auto" />
     </ThemeProvider>