feat(login): separate error messages for validation

This commit separates the error messages for credential and captcha validation on the login page. Previously, both types of errors displayed the same message, which was confusing for users. Now, distinct messages are shown depending on the error, improving user experience.

frontend/src/i18n/en.json

@@ -122,7 +122,8 @@
     "submit": "Login",
     "username": "Username",
     "usernameTaken": "Username already taken",
-    "wrongCredentials": "Wrong credentials"
+    "wrongCredentials": "Wrong credentials",
+    "captchaNeeded": "Captcha Needed"
   },
   "permanent": "Permanent",
   "prompts": {

frontend/src/i18n/ja.json

@@ -111,7 +111,8 @@
     "submit": "ログイン",
     "username": "ユーザ名",
     "usernameTaken": "Username already taken",
-    "wrongCredentials": "ユーザ名またはパスワードが間違っています。"
+    "wrongCredentials": "ユーザ名またはパスワードが間違っています。",
+    "captchaNeeded": "キャプチャが必要です"
   },
   "permanent": "永久",
   "prompts": {

frontend/src/i18n/zh-cn.json

@@ -117,7 +117,8 @@
     "submit": "登录",
     "username": "用户名",
     "usernameTaken": "用户名已经被使用",
-    "wrongCredentials": "用户名或密码错误"
+    "wrongCredentials": "用户名或密码错误",
+    "captchaNeeded": "需要验证"
   },
   "permanent": "永久",
   "prompts": {

frontend/src/i18n/zh-tw.json

@@ -111,7 +111,8 @@
     "submit": "登入",
     "username": "帳號",
     "usernameTaken": "用戶名已存在",
-    "wrongCredentials": "帳號或密碼錯誤"
+    "wrongCredentials": "帳號或密碼錯誤",
+    "captchaNeeded": "需要驗證碼"
   },
   "permanent": "永久",
   "prompts": {

frontend/src/views/Login.vue

@@ -97,7 +97,7 @@ export default {
         captcha = window.grecaptcha.getResponse();
 
         if (captcha === "") {
-          this.error = this.$t("login.wrongCredentials");
+          this.error = this.$t("login.captchaNeeded");
           return;
         }
       }