feat(front) : ameliorations UI onglets client (compta, RIB, blocs, placeholder)

- Onglet Comptabilite : grille alignee sur les autres onglets
  (grid-cols-4 gap-x-[44px] gap-y-4) en creation / modification / consultation.
- Bloc RIB toujours visible (au moins un bloc, meme vide) en creation,
  modification et consultation ; un bloc vide n'est jamais persiste.
- Blocs Contact / Adresse / RIB toujours affiches meme vides en consultation
  et modification ; suppression des messages « Aucun ... enregistre ».
- Onglets a venir (Transport, Statistiques, Rapports, Echanges) : nouveau
  composant partage ComingSoonPlaceholder (shared/components/ui) « En cours de
  dev » + gif, reutilisable par tous les modules ; remplace TabPlaceholderBlank.

frontend/modules/commercial/pages/clients/[id]/edit.vue

@@ -179,9 +179,6 @@
                             @update:model-value="(v) => contacts[index] = v"
                             @remove="askRemoveContact(index)"
                         />
-                        <p v-if="contacts.length === 0" class="text-center text-black/60">
-                            {{ t('commercial.clients.edit.emptyContacts') }}
-                        </p>
                         <div v-if="!businessReadonly" class="flex justify-center gap-6">
                             <MalioButton
                                 variant="secondary"
@@ -219,9 +216,6 @@
                             @remove="askRemoveAddress(index)"
                             @degraded="onAddressDegraded"
                         />
-                        <p v-if="addresses.length === 0" class="text-center text-black/60">
-                            {{ t('commercial.clients.edit.emptyAddresses') }}
-                        </p>
                         <div v-if="!businessReadonly" class="flex justify-center gap-6">
                             <MalioButton
                                 variant="secondary"
@@ -245,7 +239,7 @@
                 <template v-if="canAccountingView" #accounting>
                     <div class="mt-12 flex flex-col gap-6">
                         <div class="bg-white py-4 pl-[28px] pr-[60px] shadow-[0_4px_4px_0_rgba(0,0,0,0.25)]">
-                            <div class="grid grid-cols-3 gap-x-[80px] gap-y-5">
+                            <div class="grid grid-cols-4 gap-x-[44px] gap-y-4">
                                 <MalioInputText
                                     v-model="accounting.siren"
                                     :label="t('commercial.clients.form.accounting.siren')"
@@ -312,7 +306,7 @@
                                 v-bind="{ ariaLabel: t('commercial.clients.form.accounting.removeRib') }"
                                 @click="askRemoveRib(index)"
                             />
-                            <div class="grid grid-cols-3 gap-x-[80px] gap-y-5">
+                            <div class="grid grid-cols-4 gap-x-[44px] gap-y-4">
                                 <MalioInputText
                                     v-model="rib.label"
                                     :label="t('commercial.clients.form.accounting.ribLabel')"
@@ -350,10 +344,10 @@
                 </template>
 
                 <!-- Onglets non encore implementes : frame vide (navigation libre). -->
-                <template #transport><TabPlaceholderBlank /></template>
-                <template #statistics><TabPlaceholderBlank /></template>
-                <template #reports><TabPlaceholderBlank /></template>
-                <template #exchanges><TabPlaceholderBlank /></template>
+                <template #transport><ComingSoonPlaceholder /></template>
+                <template #statistics><ComingSoonPlaceholder /></template>
+                <template #reports><ComingSoonPlaceholder /></template>
+                <template #exchanges><ComingSoonPlaceholder /></template>
             </MalioTabList>
         </template>
 
@@ -495,6 +489,11 @@ function hydrate(detail: ClientDetail): void {
     contacts.value = (detail.contacts ?? []).map(mapContactToDraft)
     addresses.value = (detail.addresses ?? []).map(mapAddressToDraft)
     ribs.value = (detail.ribs ?? []).map(mapRibToDraft)
+    // Chaque bloc reste visible meme vide : si une collection est vide, on amorce
+    // un bloc vierge (non persiste tant qu'incomplet — cf. submit*/canValidate*).
+    if (contacts.value.length === 0) contacts.value.push(emptyContact())
+    if (addresses.value.length === 0) addresses.value.push(emptyAddress())
+    if (ribs.value.length === 0) ribs.value.push(emptyRib())
     // Charge les listes distributeur / courtier si une relation est deja posee.
     if (main.relationType === 'distributeur') referentials.loadDistributors().catch(() => {})
     if (main.relationType === 'courtier') referentials.loadBrokers().catch(() => {})
@@ -694,6 +693,8 @@ function askRemoveContact(index: number): void {
         const removed = contacts.value[index]
         if (removed?.id != null) removedContactIds.value.push(removed.id)
         contacts.value.splice(index, 1)
+        // Garde au moins un bloc visible (cf. amorce a l'hydratation).
+        if (contacts.value.length === 0) contacts.value.push(emptyContact())
     })
 }
 
@@ -755,6 +756,8 @@ function askRemoveAddress(index: number): void {
         const removed = addresses.value[index]
         if (removed?.id != null) removedAddressIds.value.push(removed.id)
         addresses.value.splice(index, 1)
+        // Garde au moins un bloc visible (cf. amorce a l'hydratation).
+        if (addresses.value.length === 0) addresses.value.push(emptyAddress())
     })
 }
 
@@ -833,6 +836,8 @@ function askRemoveRib(index: number): void {
         const removed = ribs.value[index]
         if (removed?.id != null) removedRibIds.value.push(removed.id)
         ribs.value.splice(index, 1)
+        // Garde au moins un bloc RIB visible (cf. amorce a l'hydratation).
+        if (ribs.value.length === 0) ribs.value.push(emptyRib())
     })
 }