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>

shopdb/core/models/communication.py

@@ -20,18 +20,30 @@ class CommunicationType(BaseModel):
 
 class Communication(BaseModel):
     """
-    Communication interface for a machine.
+    Communication interface for an asset (or legacy machine).
     Stores network config, serial settings, etc.
     """
     __tablename__ = 'communications'
 
     communicationid = db.Column(db.Integer, primary_key=True)
 
+    # New asset-based FK (preferred)
+    assetid = db.Column(
+        db.Integer,
+        db.ForeignKey('assets.assetid'),
+        nullable=True,
+        index=True,
+        comment='FK to assets table (new architecture)'
+    )
+
+    # Legacy machine FK (for backward compatibility during migration)
     machineid = db.Column(
         db.Integer,
         db.ForeignKey('machines.machineid'),
-        nullable=False
+        nullable=True,
+        comment='DEPRECATED: FK to machines table - use assetid instead'
     )
+
     comtypeid = db.Column(
         db.Integer,
         db.ForeignKey('communicationtypes.comtypeid'),
@@ -82,6 +94,7 @@ class Communication(BaseModel):
     comtype = db.relationship('CommunicationType', backref='communications')
 
     __table_args__ = (
+        db.Index('idx_comm_asset', 'assetid'),
         db.Index('idx_comm_machine', 'machineid'),
         db.Index('idx_comm_ip', 'ipaddress'),
     )