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/common/SearchSelect.vue

@@ -41,11 +41,11 @@
           v-if="openDropdown"
           class="absolute z-30 mt-1 w-full max-h-60 overflow-y-auto bg-base-100 border border-base-200 rounded-box shadow-lg"
         >
-          <div v-if="loading" class="flex items-center gap-2 px-3 py-2 text-xs text-gray-500">
+          <div v-if="loading" class="flex items-center gap-2 px-3 py-2 text-xs text-base-content/50">
             <span class="loading loading-spinner loading-xs" />
             Recherche en cours…
           </div>
-          <div v-else-if="displayedOptions.length === 0" class="px-3 py-2 text-xs text-gray-500">
+          <div v-else-if="displayedOptions.length === 0" class="px-3 py-2 text-xs text-base-content/50">
             {{ emptyText }}
           </div>
           <ul v-else class="flex flex-col">
@@ -69,7 +69,7 @@
                     {{ resolveLabel(option) }}
                   </slot>
                 </span>
-                <span v-if="resolveDescription(option)" class="text-xs text-gray-500">
+                <span v-if="resolveDescription(option)" class="text-xs text-base-content/50">
                   <slot name="option-description" :option="option">
                     {{ resolveDescription(option) }}
                   </slot>