IAV-1288/bugfix(legal-agent): add workflow-check endpoint with integration active status
- Add GET /legal/workflow-check/{userUid} and AgentWorkflowCheckResponseDTO to expose agent active state plus Slack/Teams integration active flags in one response.
- Implement LegalAgentService.getWorkflowCheck(userUid): load agent by owner admin UID, query orchestration agent-integrations for SLACK/MICROSOFT_TEAMS active status, and fallback to inactive integration flags if orchestration lookup fails.
- Add Paths.IaviaAgentServiceLegal.Legal.WORKFLOW_CHECK constant.