Migrate frontend to plugin-based asset architecture

- Add equipmentApi and computersApi to replace legacy machinesApi
- Add controller vendor/model fields to Equipment model and forms
- Fix map marker navigation to use plugin-specific IDs (equipmentid,
  computerid, printerid, networkdeviceid) instead of assetid
- Fix search to use unified Asset table with correct plugin IDs
- Remove legacy printer search that used non-existent field names
- Enable optional JWT auth for detail endpoints (public read access)
- Clean up USB plugin models (remove unused checkout model)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/components/EmbeddedLocationMap.vue

@@ -6,6 +6,7 @@
 import { ref, onMounted, onUnmounted, watch } from 'vue'
 import L from 'leaflet'
 import 'leaflet/dist/leaflet.css'
+import { currentTheme } from '../stores/theme'
 
 const props = defineProps({
   left: { type: Number, default: null },
@@ -23,11 +24,6 @@ const MAP_WIDTH = 3300
 const MAP_HEIGHT = 2550
 const bounds = [[0, 0], [MAP_HEIGHT, MAP_WIDTH]]
 
-// Detect system color scheme
-function getTheme() {
-  return window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light'
-}
-
 function initMap() {
   if (!mapContainer.value || props.left === null || props.top === null) return
 
@@ -39,8 +35,7 @@ function initMap() {
     zoomControl: true
   })
 
-  const theme = getTheme()
-  const blueprintUrl = theme === 'light'
+  const blueprintUrl = currentTheme.value === 'light'
     ? '/static/images/sitemap2025-light.png'
     : '/static/images/sitemap2025-dark.png'