feat: remove username length limit

app/src/views/ChooseUsernamePage.vue

@@ -6,11 +6,11 @@ import { TooManyRequestsError, ValidationError } from '../utils/errors'
 import { checkUsername, chooseUsername } from '../utils/auth'
 
 async function check({ username, error }) {
-  if (username && !isValidUsername(username)) {
-    error('Invalid username.')
-    return
-  }
-  if (username.length > 3) {
+  if (username) {
+    if (!isValidUsername(username)) {
+      error('Invalid username.')
+      return
+    }
     try {
       await checkUsername(username)
     } catch (err) {

app/src/views/RegisterPage.vue

@@ -48,9 +48,6 @@ async function check({ username, email, password, error }) {
     )
     return
   }
-  if (!(username && email && password)) {
-    return
-  }
   try {
     await checkUsername(username)
   } catch (err) {