fix: show/enter service duration in hours instead of minutes in admin panel

Storage stays in minutes (duration_minutes); the admin form now takes
hours (0.25 step) and the list shows the formatted "Xh Ym" duration.

src/pages/admin/AdminServices.test.tsx

@@ -56,7 +56,7 @@ describe('AdminServices', () => {
 
     await userEvent.type(screen.getByLabelText(/^id$/i), 'cornrows')
     await userEvent.type(screen.getByLabelText(/^nom$/i), 'Cornrows')
-    await userEvent.type(screen.getByLabelText(/durée en minutes/i), '120')
+    await userEvent.type(screen.getByLabelText(/durée en heures/i), '2')
     await userEvent.type(screen.getByLabelText(/prix à partir de/i), '90')
     await userEvent.type(screen.getByLabelText(/^description$/i), 'Classic style.')
     await userEvent.click(screen.getByRole('button', { name: /enregistrer le service/i }))

src/pages/admin/AdminServices.tsx

@@ -17,6 +17,12 @@ function emptyForm(): AdminService {
   return { id: '', name: '', duration_minutes: 0, price_from: 0, description: '', image: '' }
 }
 
+function formatDuration(minutes: number): string {
+  const hours = Math.floor(minutes / 60)
+  const rest = minutes % 60
+  return rest === 0 ? `${hours}h` : `${hours}h ${rest}m`
+}
+
 function AdminServices() {
   const [servicesList, setServicesList] = useState<AdminService[]>([])
   const [form, setForm] = useState<AdminService>(emptyForm())
@@ -91,7 +97,7 @@ function AdminServices() {
         <thead>
           <tr>
             <th>Nom</th>
-            <th>Durée (min)</th>
+            <th>Durée</th>
             <th>Prix à partir de</th>
             <th></th>
           </tr>
@@ -100,7 +106,7 @@ function AdminServices() {
           {servicesList.map((service) => (
             <tr key={service.id}>
               <td>{service.name}</td>
-              <td>{service.duration_minutes}</td>
+              <td>{formatDuration(service.duration_minutes)}</td>
               <td>{service.price_from} $</td>
               <td>
                 <button type="button" className={styles.buttonSecondary} onClick={() => setForm(service)}>Modifier</button>
@@ -133,12 +139,14 @@ function AdminServices() {
           />
         </label>
         <label htmlFor="service-duration">
-          Durée en minutes
+          Durée en heures
           <input
             id="service-duration"
             type="number"
-            value={form.duration_minutes}
-            onChange={(e) => setForm((f) => ({ ...f, duration_minutes: Number(e.target.value) }))}
+            step="0.25"
+            min="0"
+            value={form.duration_minutes / 60}
+            onChange={(e) => setForm((f) => ({ ...f, duration_minutes: Math.round(Number(e.target.value) * 60) }))}
             required
           />
         </label>