Refactor: eliminate "special" entity type and use DID-based logic

Replace string-based entity type matching with DID-based logic for "You" and "Unnamed" entities. Treat these as regular person entities instead of special types.

- Remove "special" type from EntitySelectionEvent interface
- Update EntityGrid to emit "You" and "Unnamed" as person entities
- Simplify SpecialEntityCard emit structure (remove entityType parameter)
- Refactor GiftedDialog to process all person entities with DID-based logic
- Update ContactGiftingView and HomeView to use DID-based entity creation
- Remove string literals "You" and "Unnamed" from method signatures

src/components/EntitySelectionStep.vue

@@ -56,9 +56,8 @@ interface EntityData {
  * Entity selection event data structure
  */
 interface EntitySelectionEvent {
-  type: "person" | "project" | "special";
-  entityType?: string;
-  data: Contact | PlanData | EntityData;
+  type: "person" | "project";
+  data: Contact | PlanData;
 }
 
 /**