Add camera and storage permissions, and implement profile picture upload functionality

lib/blocs/user/user_state.dart

@@ -78,10 +78,13 @@ class UserModel {
   /// User's phone number (optional).
   final String? phoneNumber;
   
+  /// User's profile picture URL (optional).
+  final String? profilePictureUrl;
+  
   /// Creates a new [UserModel] instance.
   /// 
   /// [id], [email], and [prenom] are required fields.
-  /// [nom], [authMethod], and [phoneNumber] are optional and can be null.
+  /// [nom], [authMethod], [phoneNumber], and [profilePictureUrl] are optional and can be null.
   UserModel({
     required this.id,
     required this.email,
@@ -89,6 +92,7 @@ class UserModel {
     this.nom,
     this.authMethod,
     this.phoneNumber,
+    this.profilePictureUrl,
   });
   
   /// Creates a [UserModel] instance from a JSON map.
@@ -103,6 +107,7 @@ class UserModel {
       nom: json['nom'],
       authMethod: json['authMethod'] ?? json['platform'],
       phoneNumber: json['phoneNumber'],
+      profilePictureUrl: json['profilePictureUrl'],
     );
   }
   
@@ -117,6 +122,7 @@ class UserModel {
       'nom': nom,
       'authMethod': authMethod,
       'phoneNumber': phoneNumber,
+      'profilePictureUrl': profilePictureUrl,
     };
   }
 }