feat: add password requirement display and enhance password validation on the signup page.

lib/components/signup/password_requirements.dart

@@ -0,0 +1,57 @@
+import 'package:flutter/material.dart';
+
+class PasswordRequirements extends StatelessWidget {
+  final String password;
+
+  const PasswordRequirements({super.key, required this.password});
+
+  bool get _hasMinLength => password.length >= 8;
+  bool get _hasUppercase => password.contains(RegExp(r'[A-Z]'));
+  bool get _hasLowercase => password.contains(RegExp(r'[a-z]'));
+  bool get _hasDigit => password.contains(RegExp(r'[0-9]'));
+  bool get _hasSpecialChar =>
+      password.contains(RegExp(r'[!@#\$%^&*(),.?":{}|<>]'));
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: [
+        const SizedBox(height: 10),
+        const Text(
+          'Votre mot de passe doit contenir :',
+          style: TextStyle(fontSize: 14, fontWeight: FontWeight.bold),
+        ),
+        const SizedBox(height: 8),
+        _buildRequirement(_hasMinLength, 'Au moins 8 caractères'),
+        _buildRequirement(_hasUppercase, 'Une majuscule'),
+        _buildRequirement(_hasLowercase, 'Une minuscule'),
+        _buildRequirement(_hasDigit, 'Un chiffre'),
+        _buildRequirement(_hasSpecialChar, 'Un caractère spécial'),
+      ],
+    );
+  }
+
+  Widget _buildRequirement(bool isMet, String text) {
+    return Padding(
+      padding: const EdgeInsets.symmetric(vertical: 2.0),
+      child: Row(
+        children: [
+          Icon(
+            isMet ? Icons.check_circle : Icons.circle_outlined,
+            color: isMet ? Colors.green : Colors.grey,
+            size: 16,
+          ),
+          const SizedBox(width: 8),
+          Text(
+            text,
+            style: TextStyle(
+              color: isMet ? Colors.green : Colors.grey,
+              fontSize: 12,
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}