feat: teller uniqueness, cashier allocation office check and interest posting report updates

fineract-branch/src/main/java/org/apache/fineract/organisation/teller/domain/TellerRepository.java

@@ -33,4 +33,6 @@ public interface TellerRepository extends JpaRepository<Teller, Long>, JpaSpecif
     Collection<Teller> findTellerByOfficeId(Long officeId);
 
     long countByDeletedFalse();
+
+    long countByOfficeIdAndDeletedFalse(Long officeId);
 }

fineract-branch/src/main/java/org/apache/fineract/organisation/teller/domain/TellerRepositoryWrapper.java

@@ -58,4 +58,9 @@ public class TellerRepositoryWrapper {
     public boolean existsAny() {
         return this.repository.countByDeletedFalse() > 0;
     }
+
+    /** Whether the branch already has a (not deleted) teller — each branch keeps one vault of its own. */
+    public boolean existsInOffice(final Long officeId) {
+        return this.repository.countByOfficeIdAndDeletedFalse(officeId) > 0;
+    }
 }

fineract-branch/src/main/java/org/apache/fineract/organisation/teller/exception/TellerAlreadyExistsException.java

@@ -28,4 +28,9 @@ public class TellerAlreadyExistsException extends AbstractPlatformDomainRuleExce
     public TellerAlreadyExistsException() {
         super(ERROR_MESSAGE_CODE, DEFAULT_ERROR_MESSAGE);
     }
+
+    public TellerAlreadyExistsException(final String officeName) {
+        super(ERROR_MESSAGE_CODE, "Cannot create teller: " + officeName + " already has a teller. Each branch has one teller.",
+                officeName);
+    }
 }