Merge develop into master (squash): ticket #102 NIR harmonisation

- Backend: DTO NIR 15 car 2A/2B, validation format+clé, warning cohérence
- BDD: nir_chiffre NOT NULL, migration pour bases existantes
- Seeds: 02 nir_chiffre, 03 Marie 2A / Fatima 99
- Frontend: nir_utils, nir_text_field, formulaire pro, mock inscription AM

Made-with: Cursor

frontend/lib/widgets/custom_app_text_field.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import 'package:google_fonts/google_fonts.dart';
 
 // Définition de l'enum pour les styles de couleur/fond
@@ -30,6 +31,7 @@ class CustomAppTextField extends StatefulWidget {
   final Iterable<String>? autofillHints;
   final TextInputAction? textInputAction;
   final ValueChanged<String>? onFieldSubmitted;
+  final List<TextInputFormatter>? inputFormatters;
 
   const CustomAppTextField({
     super.key,
@@ -54,6 +56,7 @@ class CustomAppTextField extends StatefulWidget {
     this.autofillHints,
     this.textInputAction,
     this.onFieldSubmitted,
+    this.inputFormatters,
   });
 
   @override
@@ -114,6 +117,7 @@ class _CustomAppTextFieldState extends State<CustomAppTextField> {
                   focusNode: widget.focusNode,
                   obscureText: widget.obscureText,
                   keyboardType: widget.keyboardType,
+                  inputFormatters: widget.inputFormatters,
                   autofillHints: widget.autofillHints,
                   textInputAction: widget.textInputAction,
                   onFieldSubmitted: widget.onFieldSubmitted,