Summary

Document the dependency injection container, metric factory, and C++20 concepts used throughout monitoring_system for compile-time type safety and service resolution.

Parent Issue

Part of: [EPIC] docs: Address documentation gaps across all ecosystem systems (kcenon/common_system#325)

Background (Why)

monitoring_system uses advanced C++ patterns that need documentation:

1. DI Container (di/service_registration.h) for service lifecycle management
2. Metric Factory (factory/metric_factory.h) for collector creation and configuration
3. C++20 Concepts (concepts/monitoring_concepts.h) for compile-time validation
4. Adaptive Monitor (adaptive/adaptive_monitor.h) for self-tuning behavior

Source files:

• include/kcenon/monitoring/di/service_registration.h — DI container
• include/kcenon/monitoring/factory/metric_factory.h — Collector factory
• include/kcenon/monitoring/factory/collector_adapters.h — Collector adapters
• include/kcenon/monitoring/concepts/monitoring_concepts.h — C++20 concepts
• include/kcenon/monitoring/adaptive/adaptive_monitor.h — Self-tuning monitor

Scope (What)

1. DI Container

• Service registration and resolution
• Lifecycle management (singleton, transient, scoped)
• Named services and multi-implementation
• Testing with DI (mock injection)

2. Metric Factory

• Collector registration and creation
• Configuration-driven collector selection
• Dynamic loading and unloading
• Factory customization

3. C++20 Concepts

• Available concepts (EventType, EventHandler, CollectorType, etc.)
• Compile-time validation examples
• Custom concept implementation
• Error messages when concepts are not satisfied

4. Adaptive Monitor

• Self-tuning collection intervals
• Load-based adjustment
• Adaptive sampling

5. Usage Examples

• Complete DI setup with all services
• Factory-based collector configuration
• Concept-constrained custom types

Acceptance Criteria

• DI container API documented with lifecycle patterns
• Metric factory configuration documented
• C++20 concepts listed with usage examples
• Adaptive monitor behavior documented
• Complete DI + factory setup example