feat(frontend): Portal public client + PDF download + Facturi view

- DevizPublicView: standalone public page /p/:token (no auth, no layout)
  - Loads order/tenant/lines from backend API
  - Accept/Reject buttons with feedback banners
  - Mobile-first design with service branding
- usePdf composable: fetch PDF blob from backend and trigger browser download
- PdfDownloadButton component: reusable button for deviz/invoice PDF download
- InvoicesView: table with invoice list from wa-sqlite, PDF download per row
- OrderDetailView: added PDF Deviz download button (visible when not DRAFT)
- Router: added /invoices route, portal /p/:token uses layout: 'none'
- App.vue: supports layout: 'none' for standalone pages
- AppLayout: added Facturi link in sidebar nav

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/components/orders/PdfDownloadButton.vue

@@ -0,0 +1,44 @@
+<template>
+  <button
+    @click="handleDownload"
+    :disabled="downloading"
+    class="inline-flex items-center gap-1.5 px-3 py-1.5 text-sm rounded-md border border-gray-300 text-gray-700 hover:bg-gray-50 disabled:opacity-50"
+  >
+    <svg class="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+      <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 10v6m0 0l-3-3m3 3l3-3m2 8H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" />
+    </svg>
+    {{ downloading ? 'Se descarca...' : label }}
+  </button>
+</template>
+
+<script setup>
+import { ref } from 'vue'
+import { usePdf } from '../../composables/usePdf.js'
+
+const props = defineProps({
+  type: { type: String, required: true, validator: v => ['deviz', 'invoice'].includes(v) },
+  orderId: { type: String, default: null },
+  invoiceId: { type: String, default: null },
+  nrComanda: { type: String, default: '' },
+  nrFactura: { type: String, default: '' },
+  label: { type: String, default: 'PDF' },
+})
+
+const { downloadDevizPdf, downloadInvoicePdf } = usePdf()
+const downloading = ref(false)
+
+async function handleDownload() {
+  downloading.value = true
+  try {
+    if (props.type === 'deviz') {
+      await downloadDevizPdf(props.orderId, props.nrComanda)
+    } else {
+      await downloadInvoicePdf(props.invoiceId, props.nrFactura)
+    }
+  } catch (e) {
+    alert(e.message)
+  } finally {
+    downloading.value = false
+  }
+}
+</script>