Summary

Document the unified database system integration layer at database/integrated/unified_database_system.h which provides adapters for logger_system, monitoring_system, and thread_system integration.

Parent Issue

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

Background (Why)

The unified_database_system is the primary integration point that connects the database system with the rest of the kcenon ecosystem. It provides adapters for:

• logger_system — Database-backed log storage
• monitoring_system — Database performance metrics
• thread_system — Async query execution via thread pools

Additionally, the database/protocol/database_protocol.h and database/protocol/database_protocol_container.h define the protocol layer for database operations but are undocumented.

Source files:

• database/integrated/unified_database_system.h — Main integration class
• database/integrated/unified_database_system.cpp — Implementation
• database/protocol/database_protocol.h — Protocol definitions
• database/protocol/database_protocol_container.h — Protocol container types
• database/protocol/database_protocol.cpp — Protocol implementation

Scope (What)

Create documentation covering:

1. Unified System Architecture

• How unified_database_system orchestrates multiple subsystems
• Adapter pattern usage for cross-system integration
• Initialization and bootstrap sequence

2. Logger Integration

• How database_system stores logs via logger_system adapter
• Configuration for database-backed logging
• Log table schema and retention policies

3. Monitoring Integration

• Database performance metrics exposed to monitoring_system
• Query timing, connection pool stats, error rates
• Dashboard configuration for database metrics

4. Thread System Integration

• Async query execution via thread_system adapters
• Thread pool configuration for database operations
• Connection pool thread safety model

5. Protocol Layer

• database_protocol.h message types and serialization
• database_protocol_container.h container types
• Protocol versioning and compatibility

6. Bootstrap Example

// Complete setup example
auto db_system = unified_database_system::create()
    .with_logger(logger_adapter)
    .with_monitoring(monitoring_adapter)
    .with_thread_pool(thread_adapter)
    .build();

Acceptance Criteria

• Unified system architecture documented with diagram
• All three integration adapters documented
• Protocol layer fully documented
• Bootstrap/initialization sequence explained
• Complete setup example with all integrations
• Configuration options listed