Add the printedparts plugin: 3D-printed parts storefront and kiosk

Catalog with photos and append-only print-file revisions, a stock
ledger attributing every take/restock/adjust to a badge-resolved
employee, a touch kiosk (scan bin, scan badge, keypad quantity) with a
deliberately open decrement-only take endpoint, 1x0.5in CODE128 bin
labels, low-stock email alerts to selected users, roles, or addresses,
and stock/consumption/by-person reports with a cache-vs-ledger
reconcile. Ships disabled; enable per site. Contract 0.13.0 adds the
mailer and the User/Role models to the plugin surface.

frontend/src/views/AppLayout.vue

@@ -27,6 +27,8 @@
         <div class="nav-section">Displays</div>
         <a :href="withBase('/shopfloor')" target="_blank" class="external-link">Shopfloor Dashboard</a>
         <a :href="withBase('/tv')" target="_blank" class="external-link">TV Slideshow</a>
+        <a v-if="isPluginEnabled('printedparts')" :href="withBase('/parts-kiosk')"
+           target="_blank" class="external-link">Parts Kiosk</a>
 
         <router-link v-if="authStore.isAdmin" to="/settings">Settings</router-link>
       </nav>
@@ -101,13 +103,14 @@ import ToastHost from '../components/ToastHost.vue'
 import {
   Sun, Moon, LayoutDashboard, Calendar, Map, Cog, Monitor,
   Printer, Globe, Usb, AppWindow, BookOpen, BarChart3, Bell, Image, ShieldCheck, Ruler,
-  KeyRound, LogOut
+  Box, KeyRound, LogOut
 } from 'lucide-vue-next'
 import { useAuthStore } from '../stores/auth'
 import { currentTheme, toggleTheme } from '../stores/theme'
 import { dashboardApi, notificationsApi } from '../api'
 import { getFacilityName, getSiteLogo, getServicenowUrls } from '../utils/siteSettings'
 import { withBase } from '../utils/basePath'
+import { isPluginEnabled } from '../composables/enabledPlugins'
 
 const router = useRouter()
 const route = useRoute()
@@ -147,6 +150,7 @@ const iconMap = {
   'image': Image,
   'shield': ShieldCheck,
   'ruler': Ruler,
+  'box': Box,
 }
 
 // Default navigation (used as fallback if API fails)