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/components/DocumentPreviewModal.vue

@@ -10,11 +10,11 @@
           <div class="min-w-0">
             <h3 class="font-bold text-xl truncate">
               Prévisualisation
-              <span v-if="navTotal > 1" class="text-base font-normal text-gray-500">
+              <span v-if="navTotal > 1" class="text-base font-normal text-base-content/50">
                 {{ activeIndex + 1 }} / {{ navTotal }}
               </span>
             </h3>
-            <p class="text-sm text-gray-500 truncate">
+            <p class="text-sm text-base-content/50 truncate">
               {{ activeDoc?.name || activeDoc?.filename }}<span v-if="documentDescription"> &bull; {{ documentDescription }}</span>
             </p>
           </div>
@@ -68,7 +68,7 @@
 
             <template v-else-if="previewType === 'text'">
               <div class="w-full h-full overflow-auto">
-                <div v-if="textLoading" class="flex items-center justify-center py-10 text-sm text-gray-500">
+                <div v-if="textLoading" class="flex items-center justify-center py-10 text-sm text-base-content/50">
                   <span class="loading loading-spinner loading-md mr-2" />
                   Chargement du document...
                 </div>
@@ -82,7 +82,7 @@
             </template>
 
             <template v-else>
-              <div class="text-sm text-gray-500 text-center px-6">
+              <div class="text-sm text-base-content/50 text-center px-6">
                 Prévisualisation non disponible pour ce type de document.
               </div>
             </template>