feat(ui): improve password validation display with detailed requirements

- Enhance PasswordStrengthIndicator with visual checkmarks for each requirement
- Add explicit validation for uppercase, lowercase, and number requirements
- Show clear pass/fail indicators (CheckCircle/XCircle icons) for each criterion
- Add front-end validation matching production password policy
- Display specific error messages listing all missing requirements
- Align with production standards (8+ chars, uppercase, lowercase, number)

frontend/src/pages/RegisterPage.jsx

@@ -174,14 +174,29 @@ const RegisterPage = () => {
     e.preventDefault();
     setError('');
 
-    // Validation
+    // Validation - passwords match
     if (formData.password !== formData.confirmPassword) {
       setError('Passwords do not match');
       return;
     }
 
+    // Validation - password requirements (production standards)
+    const passwordErrors = [];
     if (formData.password.length < 8) {
-      setError('Password must be at least 8 characters long');
+      passwordErrors.push('at least 8 characters');
+    }
+    if (!/[A-Z]/.test(formData.password)) {
+      passwordErrors.push('one uppercase letter');
+    }
+    if (!/[a-z]/.test(formData.password)) {
+      passwordErrors.push('one lowercase letter');
+    }
+    if (!/[0-9]/.test(formData.password)) {
+      passwordErrors.push('one number');
+    }
+
+    if (passwordErrors.length > 0) {
+      setError(`Password must contain ${passwordErrors.join(', ')}`);
       return;
     }