feat: implement Confluence, ServiceNow, and Azure DevOps REST API clients
- Confluence: OAuth2 bearer auth, list_spaces, search_pages, publish_page, update_page
- ServiceNow: Basic auth, search_incidents, create_incident, get_incident, update_incident
- Azure DevOps: OAuth2 bearer auth, search_work_items, create_work_item, get_work_item, update_work_item
- Added TicketResult.id field to support both sys_id and ticket_number
- All implementations follow TDD with mockito HTTP mocking
- 19 tests passing across all three integrations