Update JIRA ticket template

Author: max-svistunov

docs/contributing/templates/jira-ticket-template.md

@@ -1,5 +1,7 @@
 ### LCORE-???? TODO fill in title
 
+**User story** (if Story, delete if Task): As a TODO [persona], I want to TODO [action], so that TODO [reason/impact]. Use Story for user-facing changes, Task for feature work that does not represent a distinct user story.
+
 **Description**: TODO
 
 **Scope**: TODO
@@ -14,5 +16,6 @@
 
 ```text
 Read the "[section]" section in docs/design/<feature>/<feature>.md.
-Key files: [files].
+Key files to create or modify: [list].
+To verify: [how to manually test that the change works].
 ```