refactor: complete code efficiency pass (Issues #10, #14, #16)

Backend:
- Add Prisma soft-delete middleware for automatic deletedAt filtering (#10)
- Split 2758-line copilot.service.ts into focused sub-services (#14):
  - copilot-schedule.service.ts (schedule/event tools)
  - copilot-reports.service.ts (reporting/analytics tools)
  - copilot-fleet.service.ts (vehicle/driver tools)
  - copilot-vip.service.ts (VIP management tools)
  - copilot.service.ts now thin orchestrator
- Remove manual deletedAt: null from 50+ queries

Frontend:
- Create SortableHeader component for reusable table sorting (#16)
- Create useListPage hook for shared search/filter/sort state (#16)
- Update VipList, DriverList, EventList to use shared infrastructure

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/src/vehicles/vehicles.service.ts

@@ -10,7 +10,6 @@ export class VehiclesService {
   private readonly vehicleInclude = {
     currentDriver: true,
     events: {
-      where: { deletedAt: null },
       include: { driver: true, vehicle: true },
       orderBy: { startTime: 'asc' as const },
     },
@@ -29,7 +28,6 @@ export class VehiclesService {
 
   async findAll() {
     return this.prisma.vehicle.findMany({
-      where: { deletedAt: null },
       include: this.vehicleInclude,
       orderBy: { name: 'asc' },
     });
@@ -38,7 +36,6 @@ export class VehiclesService {
   async findAvailable() {
     return this.prisma.vehicle.findMany({
       where: {
-        deletedAt: null,
         status: 'AVAILABLE',
       },
       include: {
@@ -50,7 +47,7 @@ export class VehiclesService {
 
   async findOne(id: string) {
     const vehicle = await this.prisma.vehicle.findFirst({
-      where: { id, deletedAt: null },
+      where: { id },
       include: this.vehicleInclude,
     });
 
@@ -98,12 +95,10 @@ export class VehiclesService {
 
     // Fetch vehicles with only upcoming events (filtered at database level)
     const vehicles = await this.prisma.vehicle.findMany({
-      where: { deletedAt: null },
       include: {
         currentDriver: true,
         events: {
           where: {
-            deletedAt: null,
             startTime: { gt: now }, // Only fetch upcoming events
           },
           include: { driver: true, vehicle: true },