feat(am): inscription photo (picker, bytes web, photo_filename) (#120)

- ProfessionalInfoFormScreen : ImagePicker par défaut, MemoryImage, consentement si photo réelle
- AmRegistrationData : photoBytes + photoFilename ; récap étape 4
- registerAM : base64 + filename, erreurs réseau/JSON comme parents
- docs: 23_LISTE-TICKETS — issue #120

Made-with: Cursor

frontend/lib/models/am_registration_data.dart

@@ -14,7 +14,9 @@ class AmRegistrationData extends ChangeNotifier {
   // bool photoConsent = false; // Déplacé ou géré à l'étape 2
 
   // Step 2: Professional Info
-  String? photoPath; // Ajouté pour l'étape 2
+  String? photoPath; // Chemin fichier local (hors web) si pas d’octets en mémoire
+  Uint8List? photoBytes; // Galerie / web (ImagePicker)
+  String? photoFilename; // Nom pour l’API (ex. image.jpg)
   bool photoConsent = false; // Ajouté pour l'étape 2
   DateTime? dateOfBirth;
   String birthCity = ''; // Nouveau
@@ -57,6 +59,8 @@ class AmRegistrationData extends ChangeNotifier {
 
   void updateProfessionalInfo({
     String? photoPath,
+    Uint8List? photoBytes,
+    String? photoFilename,
     bool? photoConsent,
     DateTime? dateOfBirth,
     String? birthCity, // Nouveau
@@ -66,10 +70,9 @@ class AmRegistrationData extends ChangeNotifier {
     String? agrementNumber,
     int? capacity,
   }) {
-    // Allow setting photoPath to null explicitly
-    if (photoPath != null || this.photoPath != null) {
-      this.photoPath = photoPath;
-    }
+    this.photoPath = photoPath;
+    this.photoBytes = photoBytes;
+    this.photoFilename = photoFilename;
     this.photoConsent = photoConsent ?? this.photoConsent;
     this.dateOfBirth = dateOfBirth ?? this.dateOfBirth;
     this.birthCity = birthCity ?? this.birthCity; // Nouveau
@@ -101,12 +104,15 @@ class AmRegistrationData extends ChangeNotifier {
       email.isNotEmpty;
       // password n'est pas requis à l'inscription (défini après validation par lien email)
 
+  /// Photo réelle (pas seulement un placeholder asset).
+  bool get _hasUserPhoto =>
+      (photoBytes != null && photoBytes!.isNotEmpty) ||
+      (photoPath != null &&
+          photoPath!.isNotEmpty &&
+          !photoPath!.startsWith('assets/'));
+
   bool get isStep2Complete =>
-      // photoConsent is mandatory if a photo is system-required, otherwise optional.
-      // For now, let's assume if photoPath is present, consent should ideally be true.
-      // Or, make consent always mandatory if photo section exists.
-      // Based on new mockup, photo is present, so consent might be implicitly or explicitly needed.
-      (photoPath != null ? photoConsent == true : true) && // Ajuster selon la logique de consentement désirée
+      (_hasUserPhoto ? photoConsent == true : true) &&
       dateOfBirth != null &&
       birthCity.isNotEmpty &&
       birthCountry.isNotEmpty &&