refactor(ui) : improve styling, layout and responsive across all components

Rework CSS theme (app.css), navbar layout, dashboard page, machine detail,
catalog pages, and various form/display components for better consistency
and mobile responsiveness.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/pages/machine/[id].vue

@@ -1,8 +1,9 @@
 <template>
-  <main class="container mx-auto px-6 py-8">
+  <div>
+    <main class="container mx-auto px-6 py-8">
     <!-- Loading State -->
-    <div v-if="d.loading.value" class="flex justify-center items-center py-12">
-      <span class="loading loading-spinner loading-lg"></span>
+    <div v-if="d.loading.value" class="flex justify-center items-center py-16">
+      <span class="loading loading-spinner loading-lg text-primary"></span>
     </div>
 
     <!-- Machine Details -->
@@ -139,26 +140,29 @@
     <!-- Error State -->
     <div v-else class="text-center py-12">
       <div class="max-w-md mx-auto">
-        <IconLucideAlertTriangle class="w-16 h-16 mx-auto text-gray-400 mb-4" aria-hidden="true" />
-        <h3 class="text-lg font-medium text-gray-900 mb-2">Machine non trouvée</h3>
-        <p class="text-gray-500 mb-4">La machine avec l'ID "{{ machineId }}" n'existe pas ou a été supprimée.</p>
+        <div class="w-16 h-16 rounded-2xl bg-base-200 grid place-items-center mx-auto mb-5">
+          <IconLucideAlertTriangle class="w-8 h-8 text-base-content/30" aria-hidden="true" />
+        </div>
+        <h3 class="text-lg font-semibold text-base-content mb-1">Machine non trouvée</h3>
+        <p class="text-sm text-base-content/50 mb-6">La machine avec l'ID "{{ machineId }}" n'existe pas ou a été supprimée.</p>
         <NuxtLink to="/machines" class="btn btn-primary">
           Retour aux machines
         </NuxtLink>
       </div>
     </div>
-  </main>
+    </main>
 
-  <MachinePrintSelectionModal
-    :open="d.printModalOpen.value"
-    :selection="d.printSelection"
-    :components="d.components.value"
-    :pieces="d.machinePieces.value"
-    @close="d.closePrintModal"
-    @confirm="d.handlePrintConfirm"
-    @select-all="d.setAllPrintSelection(true)"
-    @deselect-all="d.setAllPrintSelection(false)"
-  />
+    <MachinePrintSelectionModal
+      :open="d.printModalOpen.value"
+      :selection="d.printSelection"
+      :components="d.components.value"
+      :pieces="d.machinePieces.value"
+      @close="d.closePrintModal"
+      @confirm="d.handlePrintConfirm"
+      @select-all="d.setAllPrintSelection(true)"
+      @deselect-all="d.setAllPrintSelection(false)"
+    />
+  </div>
 </template>
 
 <script setup>