docs: add comprehensive code comments, update README and TASKS, create training and troubleshooting guides

- Add JSDoc comments to API routes and business logic functions
- Update README.md with Phase 2 status and deployment/production notes
- Enhance TASKS.md with estimated timelines and dependencies
- Create docs/STAFF_TRAINING.md for team onboarding
- Create docs/CLIENT_ONBOARDING.md for customer experience
- Create docs/OPERATIONAL_PROCEDURES.md for daily operations
- Create docs/TROUBLESHOOTING.md for common setup issues
- Fix TypeScript errors in hq/page.tsx

components/kiosk/WalkInFlow.tsx

@@ -13,6 +13,9 @@ interface WalkInFlowProps {
   onCancel: () => void
 }
 
+/**
+ * WalkInFlow component that manages the walk-in booking process in steps.
+ */
 export function WalkInFlow({ apiKey, onComplete, onCancel }: WalkInFlowProps) {
   const [step, setStep] = useState<'services' | 'customer' | 'confirm' | 'success'>('services')
   const [loading, setLoading] = useState(false)