fix: error handling

- Remove unnecessary try-catch block in createSession function
- Add error handling for missing session ID in socket.js
- Improve error handling in connectDB function
- Add error handling middleware for server errors
- Add default export for get function in env.js

Signed-off-by: wancat <wancat@wancat.cc>

server/src/db.js

@@ -6,6 +6,7 @@ export default async function connectDB() {
     await mongoose.connect(config.db)
     console.log('Connected to MongoDB')
   } catch (err) {
-    console.log(err)
+    console.error(err)
+    process.exit(1)
   }
 }