refactoring majeur (code dupliqué, mort, ...)

- Économie : ~1240 lignes de code dupliqué
- Réduction : ~60% du code modal
- Amélioration : Cohérence et maintenabilité

src/hooks/useFormState.ts

@@ -0,0 +1,32 @@
+import { useState } from 'react';
+
+export function useFormState<T>(initialData: T) {
+  const [formData, setFormData] = useState<T>(initialData);
+  const [loading, setLoading] = useState(false);
+  const [error, setError] = useState('');
+
+  const handleChange = (e: React.ChangeEvent<HTMLInputElement | HTMLTextAreaElement>) => {
+    setFormData(prev => ({ ...prev, [e.target.name]: e.target.value }));
+  };
+
+  const resetForm = () => {
+    setFormData(initialData);
+    setError('');
+  };
+
+  const setFieldValue = (field: keyof T, value: any) => {
+    setFormData(prev => ({ ...prev, [field]: value }));
+  };
+
+  return { 
+    formData, 
+    setFormData, 
+    loading, 
+    setLoading, 
+    error, 
+    setError, 
+    handleChange, 
+    resetForm,
+    setFieldValue
+  };
+}