- backend: add parent_ticket field to JiraConfigOut/JiraConfigUpdate/_JIRA_KEYS
- backend: add get_jira_parent_ticket() helper in jira_service; use it in auto_create_test_issue() to set issue parent
- frontend/api: add jira_token_set to UserMeOut, jira_api_token to UserPreferencesUpdate, and full JiraConfigOut/Update types with getJiraConfig/updateJiraConfig/testJiraConnection functions
- frontend: expand ProfileSection with Jira API token password field (show/hide), token status badge, and account-id field
- frontend: add JiraConfigSection component (admin): enabled toggle, URL, project key, parent ticket, save + test connection
- frontend: add Jira tab (admin-only) with Link2 icon in SettingsPage sidebar