refactor: code efficiency improvements (Issues #9-13, #15, #17-20)

Backend:
- Extract shared hard-delete authorization utility (#9)
- Extract Prisma include constants per entity (#11)
- Fix N+1 query pattern in events findAll (#12)
- Extract shared date utility functions (#13)
- Move vehicle utilization filtering to DB query (#15)
- Add ParseBooleanPipe for query params
- Add CurrentDriver decorator + ResolveDriverInterceptor (#20)

Frontend:
- Extract shared form utilities (toDatetimeLocal) and enum labels (#17)
- Replace browser confirm() with styled ConfirmModal (#18)
- Add centralized query-keys.ts constants (#19)
- Clean up unused imports, add useMemo where needed (#19)
- Standardize filter button styling across list pages

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

frontend/src/components/DriverForm.tsx

@@ -1,5 +1,6 @@
 import { useState } from 'react';
 import { X } from 'lucide-react';
+import { DEPARTMENT_LABELS } from '@/lib/enum-labels';
 
 interface DriverFormProps {
   driver?: Driver | null;
@@ -112,9 +113,11 @@ export function DriverForm({ driver, onSubmit, onCancel, isSubmitting }: DriverF
               className="w-full px-3 py-2 border border-input rounded-md bg-background text-foreground focus:outline-none focus:ring-2 focus:ring-primary"
             >
               <option value="">Select Department</option>
-              <option value="OFFICE_OF_DEVELOPMENT">Office of Development</option>
-              <option value="ADMIN">Admin</option>
-              <option value="OTHER">Other</option>
+              {Object.entries(DEPARTMENT_LABELS).map(([value, label]) => (
+                <option key={value} value={value}>
+                  {label}
+                </option>
+              ))}
             </select>
           </div>