Add USB, Notifications, Network plugins and reusable EmployeeSearch component

New Plugins:
- USB plugin: Device checkout/checkin with employee lookup, checkout history
- Notifications plugin: Announcements with types, scheduling, shopfloor display
- Network plugin: Network device management with subnets and VLANs
- Equipment and Computers plugins: Asset type separation

Frontend:
- EmployeeSearch component: Reusable employee lookup with autocomplete
- USB views: List, detail, checkout/checkin modals
- Notifications views: List, form with recognition mode
- Network views: Device list, detail, form
- Calendar view with FullCalendar integration
- Shopfloor and TV dashboard views
- Reports index page
- Map editor for asset positioning
- Light/dark mode fixes for map tooltips

Backend:
- Employee search API with external lookup service
- Collector API for PowerShell data collection
- Reports API endpoints
- Slides API for TV dashboard
- Fixed AppVersion model (removed BaseModel inheritance)
- Added checkout_name column to usbcheckouts table

Styling:
- Unified detail page styles
- Improved pagination (page numbers instead of prev/next)
- Dark/light mode theme improvements

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

frontend/src/views/AppLayout.vue

@@ -17,21 +17,42 @@
 
       <nav class="sidebar-nav">
         <router-link to="/">Dashboard</router-link>
+        <router-link to="/calendar">Calendar</router-link>
         <router-link to="/map">Map</router-link>
+
+        <div class="nav-section">Assets</div>
         <router-link to="/machines">Equipment</router-link>
         <router-link to="/pcs">PCs</router-link>
         <router-link to="/printers">Printers</router-link>
+        <router-link to="/network">Network Devices</router-link>
+        <router-link to="/usb">USB Devices</router-link>
+
+        <div class="nav-section">Information</div>
         <router-link to="/applications">Applications</router-link>
         <router-link to="/knowledgebase">Knowledge Base</router-link>
+        <router-link to="/notifications">Notifications</router-link>
+        <router-link to="/reports">Reports</router-link>
+
+        <div class="nav-section">Displays</div>
+        <a href="/shopfloor" target="_blank" class="external-link">Shopfloor Dashboard</a>
+        <a href="/tv" target="_blank" class="external-link">TV Slideshow</a>
+
         <router-link v-if="authStore.isAdmin" to="/settings">Settings</router-link>
       </nav>
 
-      <div class="user-menu">
-        <template v-if="authStore.isAuthenticated">
-          <div class="username">{{ authStore.username }}</div>
-          <button class="btn btn-secondary" @click="handleLogout">Logout</button>
-        </template>
-        <router-link v-else to="/login" class="btn btn-primary">Login</router-link>
+      <div class="sidebar-footer">
+        <button class="theme-toggle" @click="toggleTheme" :title="currentTheme === 'dark' ? 'Switch to light mode' : 'Switch to dark mode'">
+          <span v-if="currentTheme === 'dark'">☀️ Light</span>
+          <span v-else>🌙 Dark</span>
+        </button>
+
+        <div class="user-menu">
+          <template v-if="authStore.isAuthenticated">
+            <div class="username">{{ authStore.username }}</div>
+            <button class="btn btn-secondary" @click="handleLogout">Logout</button>
+          </template>
+          <router-link v-else to="/login" class="btn btn-primary">Login</router-link>
+        </div>
       </div>
     </aside>
 
@@ -45,6 +66,7 @@
 import { ref } from 'vue'
 import { useRouter } from 'vue-router'
 import { useAuthStore } from '../stores/auth'
+import { currentTheme, toggleTheme } from '../stores/theme'
 
 const router = useRouter()
 const authStore = useAuthStore()