Add:Login validation & error alerts for user safety

Frontend-Learner/pages/auth/login.vue

@@ -30,7 +30,11 @@ const loginForm = reactive({
 // Validation rules definition
 const loginRules = {
   email: { 
-    rules: { required: true, email: true }, 
+    rules: { 
+      required: true, 
+      email: true,
+      custom: (val: string) => /[\u0E00-\u0E7F]/.test(val) ? 'ห้ามใส่ภาษาไทย' : null
+    }, 
     label: 'อีเมล',
     messages: {
       required: 'กรุณากรอกอีเมลของคุณ',
@@ -38,7 +42,11 @@ const loginRules = {
     }
   },
   password: { 
-    rules: { required: true, minLength: 8 }, 
+    rules: { 
+      required: true, 
+      minLength: 8,
+      custom: (val: string) => /[\u0E00-\u0E7F]/.test(val) ? 'ห้ามใส่ภาษาไทย' : null
+    }, 
     label: 'รหัสผ่าน',
     messages: {
       required: 'กรุณากรอกรหัสผ่าน',
@@ -55,9 +63,14 @@ const loginRules = {
  * Handles input updates, stripping Thai characters and clearing errors.
  */
 const handleInput = (field: keyof typeof loginForm, value: string) => {
-  // Remove Thai characters range \u0E00-\u0E7F
-  loginForm[field] = value.replace(/[\u0E00-\u0E7F]/g, '')
-  clearFieldError(field)
+  loginForm[field] = value
+  if (/[\u0E00-\u0E7F]/.test(value)) {
+    errors.value[field] = 'ห้ามใส่ภาษาไทย'
+  } else {
+    if (errors.value[field] === 'ห้ามใส่ภาษาไทย') {
+      clearFieldError(field)
+    }
+  }
 }
 
 const handleLogin = async () => {