Summary

Create deprecation plan for native logger_system::log_level API in favor of common::interfaces::log_level.

Part of #317

What (Problem)

The logger class has dual API:

• ILogger interface using common::interfaces::log_level
• Native API using logger_system::log_level

This creates confusion about which API to use.

Why (Rationale)

• Single source of truth: One log_level type reduces confusion
• Interface compliance: Align with common_system interfaces
• Future compatibility: Prepare for major version migration

How (Solution)

1. Mark native log_level methods as [[deprecated]]
2. Document migration timeline
3. Add deprecation warnings
4. Plan removal in next major version

Acceptance Criteria

• Native log_level methods marked as [[deprecated]]
• Migration guide documented
• Timeline established

Labels

• refactor
• api-design
• deprecation