chore: raise custom URL minlength limit

Signed-off-by: Evan Song <[email protected]>

apps/frontend/src/pages/servers/manage/[id]/options/network.vue

@@ -67,7 +67,7 @@
             .modrinth.gg
           </div>
           <span v-if="!isValidSubdomain" class="text-sm text-rose-400">
-            Subdomain must be at least 3 characters long and can only contain alphanumeric
+            Subdomain must be at least 5 characters long and can only contain alphanumeric
             characters, dashes, and underscores.
           </span>
         </div>
@@ -252,7 +252,7 @@ const newAllocationPort = ref(0);
 
 const hasUnsavedChanges = computed(() => serverSubdomain.value !== data?.value?.net?.domain);
 
-const isValidSubdomain = computed(() => /^[a-zA-Z0-9-_]{3,}$/.test(serverSubdomain.value));
+const isValidSubdomain = computed(() => /^[a-zA-Z0-9-_]{5,}$/.test(serverSubdomain.value));
 
 const addNewAllocation = async () => {
   if (!newAllocationName.value) return;