Fix Purchase Order modal and reorganize documentation

Frontend Changes:
- Fix runtime error: Remove undefined handleModify reference from ActionQueueCard in DashboardPage
- Migrate PurchaseOrderDetailsModal to use correct PurchaseOrderItem type from purchase_orders service
- Fix item display: Parse unit_price as string (Decimal) instead of number
- Use correct field names: item_notes instead of notes
- Remove deprecated PurchaseOrder types from suppliers.ts to prevent type conflicts
- Update CreatePurchaseOrderModal to use unified types
- Clean up API exports: Remove old PO hooks re-exported from suppliers
- Add comprehensive translations for PO modal (en, es, eu)

Documentation Reorganization:
- Move WhatsApp implementation docs to docs/03-features/notifications/whatsapp/
- Move forecast validation docs to docs/03-features/forecasting/
- Move specification docs to docs/03-features/specifications/
- Move deployment docs (Colima, K8s, VPS sizing) to docs/05-deployment/
- Archive completed implementation summaries to docs/archive/implementation-summaries/
- Delete obsolete FRONTEND_CHANGES_NEEDED.md
- Standardize filenames to lowercase with hyphens

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/src/api/index.ts

@@ -593,8 +593,6 @@ export {
   useTopSuppliers,
   usePendingApprovalSuppliers,
   useSuppliersByType,
-  usePurchaseOrders,
-  usePurchaseOrder,
   useDeliveries,
   useDelivery,
   useSupplierPerformanceMetrics,
@@ -603,9 +601,6 @@ export {
   useUpdateSupplier,
   useDeleteSupplier,
   useApproveSupplier,
-  useCreatePurchaseOrder,
-  useUpdatePurchaseOrder,
-  useApprovePurchaseOrder,
   useCreateDelivery,
   useUpdateDelivery,
   useConfirmDeliveryReceipt,