Migración a shadcn-vue + Tailwind CSS v4

- Tailwind CSS v4 con @tailwindcss/vite
- shadcn-vue: 19 componentes UI (button, card, dialog, table, select,
  tabs, sidebar, separator, breadcrumb, badge, avatar, dropdown-menu,
  tooltip, input, switch, sheet, skeleton)
- Sidebar collapsible con íconos Lucide
- Theme Teloprax en CSS variables (rojo #E63946, negro #1A1A2E)
- LoginView, DashboardView, CalendarView, SchedulerView migrados
- Eliminado AppShell.vue manual (reemplazado por SidebarProvider)
- Layout con breadcrumb, sidebar trigger, header unificado

src/components/ui/sheet/SheetHeader.vue

@@ -0,0 +1,15 @@
+<script setup lang="ts">
+import type { HTMLAttributes } from 'vue'
+import { cn } from '@/lib/utils'
+
+const props = defineProps<{ class?: HTMLAttributes['class'] }>()
+</script>
+
+<template>
+  <div
+    data-slot="sheet-header"
+    :class="cn('gap-0.5 p-4 flex flex-col', props.class)"
+  >
+    <slot />
+  </div>
+</template>