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/Welcome.vue

@@ -1,18 +1,10 @@
 <script setup lang="ts">
 import { Head, Link } from '@inertiajs/vue3';
-import {
-    Building2,
-    Calendar,
-    FileCheck,
-    Mail,
-    Shield,
-    Users,
-} from 'lucide-vue-next';
+import { Calendar, FileCheck, Mail, Shield, Users } from 'lucide-vue-next';
 import AppLogoIcon from '@/components/AppLogoIcon.vue';
 import { Button } from '@/components/ui/button';
 import {
     Card,
-    CardContent,
     CardDescription,
     CardHeader,
     CardTitle,