Add form field preservation in gifting flow

- Preserve description, amount, and unit code when navigating between gifting steps
- Add form field props to EntitySelectionStep and GiftedDialog components
- Update ContactGiftingView to handle form state persistence in URL parameters

src/components/EntitySelectionStep.vue

@@ -136,6 +136,16 @@ export default class EntitySelectionStep extends Vue {
   @Prop()
   receiver?: EntityData | null;
 
+  /** Form field values to preserve when navigating to "Show All" */
+  @Prop({ default: "" })
+  description!: string;
+
+  @Prop({ default: "0" })
+  amountInput!: string;
+
+  @Prop({ default: "HUR" })
+  unitCode!: string;
+
   /** Notification function from parent component */
   @Prop()
   notify?: (notification: NotificationIface, timeout?: number) => void;
@@ -228,6 +238,10 @@ export default class EntitySelectionStep extends Vue {
       stepType: this.stepType,
       giverEntityType: this.giverEntityType,
       recipientEntityType: this.recipientEntityType,
+      // Form field values to preserve
+      description: this.description,
+      amountInput: this.amountInput,
+      unitCode: this.unitCode,
       ...(this.stepType === "giver"
         ? {
             recipientProjectId: this.toProjectId || "",