feat: implement Story 2.2 — Priority Alerts Panel with UI fixes

Add PriorityAlertsPanel component to the dashboard, update DashboardController
with alert logic, and apply misc UI fixes across sidebar, forms, and pages.
Includes epic-1 retrospective and sprint status update.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

resources/js/pages/clients/Show.vue

@@ -1,7 +1,6 @@
 <script setup lang="ts">
 import { Head, Link } from '@inertiajs/vue3';
 import { Building2, FileText, FolderOpen } from 'lucide-vue-next';
-import { computed } from 'vue';
 import DeclarationCalendar from '@/components/clients/DeclarationCalendar.vue';
 import Heading from '@/components/Heading.vue';
 import { Badge } from '@/components/ui/badge';