feat: comprehensive update with Signal, Copilot, themes, and PDF features

## Signal Messaging Integration
- Added SignalService for sending messages to drivers via Signal
- SignalMessage model for tracking message history
- Driver chat modal for real-time messaging
- Send schedule via Signal (ICS + PDF attachments)

## AI Copilot
- Natural language interface for VIP Coordinator
- Capabilities: create VIPs, schedule events, assign drivers
- Help and guidance for users
- Floating copilot button in UI

## Theme System
- Dark/light/system theme support
- Color scheme selection (blue, green, purple, orange, red)
- ThemeContext for global state
- AppearanceMenu in header

## PDF Schedule Export
- VIPSchedulePDF component for schedule generation
- PDF settings (header, footer, branding)
- Preview PDF in browser
- Settings stored in database

## Database Migrations
- add_signal_messages: SignalMessage model
- add_pdf_settings: Settings model for PDF config
- add_reminder_tracking: lastReminderSent for events
- make_driver_phone_optional: phone field nullable

## Event Management
- Event status service for automated updates
- IN_PROGRESS/COMPLETED status tracking
- Reminder tracking for notifications

## UI/UX Improvements
- Driver schedule modal
- Improved My Schedule page
- Better error handling and loading states
- Responsive design improvements

## Other Changes
- AGENT_TEAM.md documentation
- Seed data improvements
- Ability factory updates
- Driver profile page

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

backend/package.json

@@ -24,6 +24,7 @@
     "prisma:seed": "ts-node prisma/seed.ts"
   },
   "dependencies": {
+    "@anthropic-ai/sdk": "^0.72.1",
     "@casl/ability": "^6.8.0",
     "@casl/prisma": "^1.6.1",
     "@nestjs/axios": "^4.0.1",
@@ -35,13 +36,16 @@
     "@nestjs/passport": "^10.0.3",
     "@nestjs/platform-express": "^10.3.0",
     "@prisma/client": "^5.8.1",
+    "@types/pdfkit": "^0.17.4",
     "axios": "^1.6.5",
     "class-transformer": "^0.5.1",
     "class-validator": "^0.14.0",
+    "ics": "^3.8.1",
     "ioredis": "^5.3.2",
     "jwks-rsa": "^3.1.0",
     "passport": "^0.7.0",
     "passport-jwt": "^4.0.1",
+    "pdfkit": "^0.17.2",
     "reflect-metadata": "^0.1.14",
     "rxjs": "^7.8.1"
   },
@@ -51,6 +55,7 @@
     "@nestjs/testing": "^10.3.0",
     "@types/express": "^4.17.21",
     "@types/jest": "^29.5.11",
+    "@types/multer": "^2.0.0",
     "@types/node": "^20.10.6",
     "@types/passport-jwt": "^4.0.0",
     "@types/supertest": "^6.0.2",