feat(dimentorin): confirm payment auto-confirms linked session

- confirm_payment now transitions linked session pending->confirmed
- e2e verified: book -> create payment -> admin confirm -> session confirmed + payment paid

imphnen-dimentorin/src/payments/application/payment_service.rs

@@ -142,9 +142,16 @@ impl PaymentService for PaymentServiceImpl {
 				"Payment is not pending".into(),
 			));
 		}
-		self.payment_repo
+		let paid = self.payment_repo
 			.update_status(id, "paid", Some(payment.external_ref.clone().unwrap_or_default()))
-			.await
+			.await?;
+		// Confirm the linked session so mentor/mentee can proceed with the call.
+		if let Some(mut session) = self.session_repo.find_by_id(payment.session_id).await? {
+			session.status = "confirmed".to_string();
+			session.updated_at = Utc::now();
+			self.session_repo.update(payment.session_id, session).await?;
+		}
+		Ok(paid)
 	}
 
 	async fn get_mentee_payments(