Summary

Normalize database_server integration gates to KCENON_HAS_*.

5W1H Specification

• Who: database_server maintainers
• What: Replace BUILD_WITH_* checks in gateway/tests
• Where: gateway sources and integration tests
• When: TBD
• Why: Consistent integration gating across repos
• How: Include feature_flags header and update macros

Parent Issue

kcenon/common_system#223

Tasks

• Include feature_flags.h in gateway components
• Replace BUILD_WITH_CONTAINER_SYSTEM / COMMON_SYSTEM / THREAD_SYSTEM / MONITORING_SYSTEM
  with KCENON_HAS_* equivalents
• Update docs to reference KCENON_* macros

Acceptance Criteria

• Integration checks use KCENON_HAS_*
• Tests pass with existing build options