Major Enhancement: NestJS Migration + CASL Authorization + Error Handling

Complete rewrite from Express to NestJS with enterprise-grade features:

## Backend Improvements
- Migrated from Express to NestJS 11.0.1 with TypeScript
- Implemented Prisma ORM 7.3.0 for type-safe database access
- Added CASL authorization system replacing role-based guards
- Created global exception filters with structured logging
- Implemented Auth0 JWT authentication with Passport.js
- Added vehicle management with conflict detection
- Enhanced event scheduling with driver/vehicle assignment
- Comprehensive error handling and logging

## Frontend Improvements
- Upgraded to React 19.2.0 with Vite 7.2.4
- Implemented CASL-based permission system
- Added AbilityContext for declarative permissions
- Created ErrorHandler utility for consistent error messages
- Enhanced API client with request/response logging
- Added War Room (Command Center) dashboard
- Created VIP Schedule view with complete itineraries
- Implemented Vehicle Management UI
- Added mock data generators for testing (288 events across 20 VIPs)

## New Features
- Vehicle fleet management (types, capacity, status tracking)
- Complete 3-day Jamboree schedule generation
- Individual VIP schedule pages with PDF export (planned)
- Real-time War Room dashboard with auto-refresh
- Permission-based navigation filtering
- First user auto-approval as administrator

## Documentation
- Created CASL_AUTHORIZATION.md (comprehensive guide)
- Created ERROR_HANDLING.md (error handling patterns)
- Updated CLAUDE.md with new architecture
- Added migration guides and best practices

## Technical Debt Resolved
- Removed custom authentication in favor of Auth0
- Replaced role checks with CASL abilities
- Standardized error responses across API
- Implemented proper TypeScript typing
- Added comprehensive logging

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

backend/src/auth/strategies/jwt.strategy.ts

@@ -0,0 +1,75 @@
+import { Injectable, UnauthorizedException, Logger } from '@nestjs/common';
+import { PassportStrategy } from '@nestjs/passport';
+import { ConfigService } from '@nestjs/config';
+import { Strategy, ExtractJwt } from 'passport-jwt';
+import { passportJwtSecret } from 'jwks-rsa';
+import { AuthService } from '../auth.service';
+import { HttpService } from '@nestjs/axios';
+import { firstValueFrom } from 'rxjs';
+
+@Injectable()
+export class JwtStrategy extends PassportStrategy(Strategy) {
+  private readonly logger = new Logger(JwtStrategy.name);
+
+  constructor(
+    private configService: ConfigService,
+    private authService: AuthService,
+    private httpService: HttpService,
+  ) {
+    super({
+      secretOrKeyProvider: passportJwtSecret({
+        cache: true,
+        rateLimit: true,
+        jwksRequestsPerMinute: 5,
+        jwksUri: `${configService.get('AUTH0_ISSUER')}.well-known/jwks.json`,
+      }),
+      jwtFromRequest: ExtractJwt.fromAuthHeaderAsBearerToken(),
+      audience: configService.get('AUTH0_AUDIENCE'),
+      issuer: configService.get('AUTH0_ISSUER'),
+      algorithms: ['RS256'],
+      passReqToCallback: true, // We need the request to get the token
+    });
+  }
+
+  async validate(req: any, payload: any) {
+    // Extract token from Authorization header
+    const token = req.headers.authorization?.replace('Bearer ', '');
+
+    // Fetch user info from Auth0 /userinfo endpoint
+    try {
+      const userInfoUrl = `${this.configService.get('AUTH0_ISSUER')}userinfo`;
+
+      const response = await firstValueFrom(
+        this.httpService.get(userInfoUrl, {
+          headers: {
+            Authorization: `Bearer ${token}`,
+          },
+        }),
+      );
+
+      // Merge userinfo data into payload
+      const userInfo = response.data;
+
+      payload.email = userInfo.email || payload.email;
+      payload.name = userInfo.name || payload.name;
+      payload.picture = userInfo.picture || payload.picture;
+      payload.email_verified = userInfo.email_verified;
+    } catch (error) {
+      this.logger.warn(`Failed to fetch user info: ${error.message}`);
+      // Continue with payload-only data (fallbacks will apply)
+    }
+
+    // Get or create user from Auth0 token
+    const user = await this.authService.validateUser(payload);
+
+    if (!user) {
+      throw new UnauthorizedException('User not found');
+    }
+
+    if (!user.isApproved) {
+      throw new UnauthorizedException('User account pending approval');
+    }
+
+    return user;
+  }
+}