Add health check endpoint to FastTrack component

[HyeockJinKim]

Description

Implement a /health endpoint for the FastTrack component to provide health status information.

Acceptance Criteria

• Add /health endpoint to FastTrack REST API
• Return component status (healthy/unhealthy)
• Include model serving status
• Include backend connectivity status
• Include basic metadata (version, uptime, etc.)
• Return HTTP 200 for healthy state
• Return HTTP 503 for unhealthy state
• Add unit tests for the endpoint
• Update API documentation

Technical Details

• Path: /health
• Method: GET
• No authentication required for basic health check
• Should verify model serving infrastructure status
• Response format should be consistent with other components

JIRA Issue: BA-2427