Enhance frontend styling and accessibility features

- Updated .dockerignore to exclude backup directory with root-only permissions from build context.
- Added new CSS variables for card radius and transition duration in app.css.
- Implemented consistent focus ring styles for interactive elements to improve accessibility.
- Refactored card components across various pages to utilize a unified card style, enhancing visual consistency.
- Improved button styles with touch manipulation support for better user interaction on mobile devices.

frontend-nuxt/pages/admin/users/[username].vue

@@ -1,5 +1,5 @@
 <template>
-  <div class="container mx-auto p-4 max-w-lg">
+  <div class="container mx-auto p-4 max-w-2xl min-w-0">
     <h1 class="text-2xl font-bold mb-6">{{ isNew ? 'New user' : `Edit ${username}` }}</h1>
 
     <form @submit.prevent="submit" class="flex flex-col gap-4">
@@ -9,7 +9,7 @@
           id="user"
           v-model="form.user"
           type="text"
-          class="input"
+          class="input min-h-11 touch-manipulation"
           required
           :readonly="!isNew"
         />
@@ -30,15 +30,15 @@
       </fieldset>
       <p v-if="error" class="text-error text-sm">{{ error }}</p>
       <div class="flex gap-2">
-        <button type="submit" class="btn btn-primary" :disabled="loading">
+        <button type="submit" class="btn btn-primary min-h-11 touch-manipulation" :disabled="loading">
           <span v-if="loading" class="loading loading-spinner loading-sm" />
           <span v-else>Save</span>
         </button>
-        <NuxtLink to="/admin" class="btn btn-ghost">Back</NuxtLink>
+        <NuxtLink to="/admin" class="btn btn-ghost min-h-11 touch-manipulation">Back</NuxtLink>
         <button
           v-if="!isNew"
           type="button"
-          class="btn btn-error btn-outline ml-auto"
+          class="btn btn-error btn-outline ml-auto min-h-11 touch-manipulation"
           :disabled="loading"
           @click="confirmDelete"
         >