Critical regression fix - subsystems were hardcoded instead of reading user settings.
Added CreateDefaultSubsystems to queries/subsystems.go.
ConfigService now queries agent_subsystems table for actual user configuration.
AgentLifecycleService creates default subsystems when creating new agents.
Respects user-configured enabled/auto_run settings from UI.
Created centralized ConfigService for configuration management.
Added deprecation comments to ConfigBuilder and AgentBuilder.
Platform-specific defaults centralized in one place.
Removed placeholder ConfigService from agent_lifecycle.go.
Created centralized lifecycle service to handle new, upgrade, and rebuild operations.
Added deprecation notices to old handlers (agent_setup, build_orchestrator, agent_build).
Foundation for consolidating duplicate agent lifecycle logic.
