IAV-1288/bugfix(public-tender): workflow-check API for agent and Slack/Teams integration status
- Add GET /agent/workflow-check/{userUid} (Paths.Agent.WORKFLOW_CHECK) returning AgentWorkflowCheckResponseDTO (agent active + slackIntegrationActive + teamsIntegrationActive).
- PublicMarketAgentServiceImpl: load agent by owner admin UID, call orchestration agent-integrations for the agent, map SLACK / MICROSOFT_TEAMS active from response; on orchestration failure, log and treat integrations as inactive.
- Add AgentIntegrationListResponseDTO for orchestration list deserialization.