Add super-admin Administration section and restructure global vs company settings

- Add Administration sidebar section (super-admin only) with Companies, Users, and Global Settings pages
- Add super-admin middleware, controllers, and API routes under /api/v1/super-admin/
- Allow super-admins to manage all companies and users across tenants
- Add user impersonation with short-lived tokens, audit logging, and UI banner
- Move system-level settings (Mail, PDF, Backup, Update, File Disk) from per-company to Administration > Global Settings
- Convert save_pdf_to_disk from CompanySetting to global Setting
- Add per-company mail configuration overrides (optional, falls back to global)
- Add CompanyMailConfigService to apply company mail config before sending emails

resources/scripts/admin/components/ImpersonationBanner.vue

@@ -0,0 +1,41 @@
+<template>
+  <div
+    v-if="isImpersonating"
+    class="fixed top-0 left-0 right-0 z-50 flex items-center justify-center px-4 py-2 text-sm font-medium text-white bg-orange-600"
+  >
+    <BaseIcon name="ExclamationTriangleIcon" class="w-4 h-4 mr-2" />
+    <span>{{ $t('administration.users.impersonating_banner') }}</span>
+    <button
+      class="ml-4 px-3 py-1 text-xs font-semibold text-orange-600 bg-white rounded hover:bg-orange-50"
+      :disabled="isStopping"
+      @click="stopImpersonating"
+    >
+      {{ $t('administration.users.stop_impersonating') }}
+    </button>
+  </div>
+</template>
+
+<script setup>
+import { computed, ref } from 'vue'
+import Ls from '@/scripts/services/ls.js'
+import { useAdministrationStore } from '@/scripts/admin/stores/administration'
+
+const administrationStore = useAdministrationStore()
+let isStopping = ref(false)
+
+const isImpersonating = computed(() => {
+  return Ls.get('admin.impersonating') === 'true'
+})
+
+async function stopImpersonating() {
+  isStopping.value = true
+
+  try {
+    await administrationStore.stopImpersonating()
+  } catch {
+    // Token already cleaned up in store action
+  }
+
+  window.location.href = '/admin/administration/users'
+}
+</script>