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/components/Modal.vue

@@ -72,13 +72,14 @@ function handleEscape(e) {
 }
 
 .modal-container {
-  background: white;
+  background: var(--bg-card-solid);
   border-radius: 8px;
   box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
   display: flex;
   flex-direction: column;
   max-height: 90vh;
   overflow: hidden;
+  color: var(--text);
 }
 
 .modal-small {
@@ -106,7 +107,7 @@ function handleEscape(e) {
   align-items: center;
   justify-content: space-between;
   padding: 1rem 1.5rem;
-  border-bottom: 1px solid #e0e0e0;
+  border-bottom: 1px solid var(--border);
 }
 
 .modal-header h3 {
@@ -119,13 +120,13 @@ function handleEscape(e) {
   border: none;
   font-size: 1.5rem;
   cursor: pointer;
-  color: #666;
+  color: var(--text-light);
   padding: 0;
   line-height: 1;
 }
 
 .modal-close:hover {
-  color: #333;
+  color: var(--text);
 }
 
 .modal-body {
@@ -136,7 +137,7 @@ function handleEscape(e) {
 
 .modal-footer {
   padding: 1rem 1.5rem;
-  border-top: 1px solid #e0e0e0;
+  border-top: 1px solid var(--border);
   display: flex;
   justify-content: flex-end;
   gap: 0.5rem;