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/machine/MachineComponentsCard.vue

@@ -1,5 +1,5 @@
 <template>
-  <div class="card bg-base-100 shadow-lg">
+  <div class="card bg-base-100 shadow-sm">
     <div class="card-body">
       <div class="flex justify-between items-center mb-4">
         <h2 class="card-title">Composants</h2>