- Add Ping method to PostgresProfileStore to check database connection status
- Add Ping method to ProfileRepository interface
- Add /api/v1/health/live endpoint for liveness checks (always returns alive if service is running)
- Add /api/v1/health/ready endpoint for readiness checks with database connectivity validation
- Add readinessHandler that returns SERVICE_UNAVAILABLE status when database ping fails
- Add DatabaseConfig struct with DSN field for Postgres connection string
- Add package documentation comments for ES2Config/DatabaseConfig/LoadES2Config
- Normalize ES2Config field alignment for BaseURL/APIKey/InsecureSkipVerify/FunctionalityRequesterID
- Remove InMemoryProfileStore struct and all methods (Create/Get/List/UpdateState/Delete) from profile.go
- Remove sync package import