feat(dashboard): Add i18n support for action buttons

- Create getActionLabelKey() mapper function for action types
- Map action types (approve_po, call_supplier, etc.) to i18n keys
- Extract parameters from metadata (amount, supplier, customer, hours)
- Update button rendering to use translations instead of backend strings

Translation updates:
- Add missing action keys: reject_po, complete_receipt, mark_received
- Spanish translations: "Rechazar pedido", "Completar recepción", etc.
- Basque translations: "Baztertu eskaera", "Osatu stockaren harrera", etc.

Action buttons now respect user's language preference (EN/ES/EU)
instead of showing hardcoded backend strings.

Fixes: Issue #4 - Missing i18n for action buttons

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

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

frontend/src/components/dashboard/UnifiedActionQueueCard.tsx

@@ -110,6 +110,71 @@ function EscalationBadge({ alert }: { alert: EnrichedAlert }) {
   );
 }
 
+/**
+ * Map action type to i18n translation key with extracted parameters
+ */
+function getActionLabelKey(actionType: string, metadata?: Record<string, any>): { key: string; params: Record<string, any> } {
+  const actionTypeMap: Record<string, { key: string; extractParams?: (meta: Record<string, any>) => Record<string, any> }> = {
+    'approve_po': {
+      key: 'alerts:actions.approve_po',
+      extractParams: (meta) => ({ amount: meta.amount || meta.po_amount || 0 })
+    },
+    'reject_po': {
+      key: 'alerts:actions.reject_po',
+      extractParams: () => ({})
+    },
+    'call_supplier': {
+      key: 'alerts:actions.call_supplier',
+      extractParams: (meta) => ({ supplier: meta.supplier || meta.name || 'Supplier', phone: meta.phone || '' })
+    },
+    'open_reasoning': {
+      key: 'alerts:actions.see_reasoning',
+      extractParams: () => ({})
+    },
+    'complete_stock_receipt': {
+      key: 'alerts:actions.complete_receipt',
+      extractParams: () => ({})
+    },
+    'mark_delivery_received': {
+      key: 'alerts:actions.mark_received',
+      extractParams: () => ({})
+    },
+    'adjust_production': {
+      key: 'alerts:actions.adjust_production',
+      extractParams: () => ({})
+    },
+    'navigate': {
+      key: 'alerts:actions.navigate',
+      extractParams: () => ({})
+    },
+    'notify_customer': {
+      key: 'alerts:actions.notify_customer',
+      extractParams: (meta) => ({ customer: meta.customer_name || meta.customer || 'Customer' })
+    },
+    'snooze': {
+      key: 'alerts:actions.snooze',
+      extractParams: (meta) => ({ hours: meta.duration_hours || meta.hours || 4 })
+    },
+    'dismiss': {
+      key: 'alerts:actions.dismiss',
+      extractParams: () => ({})
+    },
+    'mark_read': {
+      key: 'alerts:actions.mark_read',
+      extractParams: () => ({})
+    },
+    'cancel_auto_action': {
+      key: 'alerts:actions.cancel_auto_action',
+      extractParams: () => ({})
+    },
+  };
+
+  const config = actionTypeMap[actionType] || { key: 'alerts:actions.navigate', extractParams: () => ({}) };
+  const params = config.extractParams ? config.extractParams(metadata || {}) : {};
+
+  return { key: config.key, params };
+}
+
 function ActionCard({ alert, showEscalationBadge = false, onActionSuccess, onActionError }: ActionCardProps) {
   const [expanded, setExpanded] = useState(false);
   const [loadingAction, setLoadingAction] = useState<string | null>(null);
@@ -305,7 +370,10 @@ function ActionCard({ alert, showEscalationBadge = false, onActionSuccess, onAct
                     }}
                     className={`${isPrimary ? 'font-semibold' : ''} sm:w-auto w-full`}
                   >
-                    {action.label}
+                    {(() => {
+                      const { key, params } = getActionLabelKey(action.type, action.metadata);
+                      return String(t(key, params));
+                    })()}
                     {action.estimated_time_minutes && !isLoading && (
                       <span className="ml-1 opacity-60 text-xs">({action.estimated_time_minutes}m)</span>
                     )}