Closes #329

Summary

This PR adds the Korean translation of the cross-system integration guide to complete issue #329.

Changes

• Korean Translation: Added docs/INTEGRATION_GUIDE.kr.md (2369 lines)
• Complete Coverage: All sections from the English version translated
  • Ecosystem dependency map (7 systems)
  • Integration patterns (unified bootstrapper, manual adapter wiring, service container, lifecycle management)
  • 4 common integration scenarios (Web API Server, Data Pipeline, Monitoring Stack, Full Stack Application)
  • Configuration management across systems
  • Error handling and propagation patterns
  • Initialization and shutdown sequences
  • Complete example application with build configuration

Translation Approach

• Technical Terms: Kept in English (e.g., ILogger, Result<T>, unified_bootstrapper)
• Code Examples: Preserved as-is with Korean comments where appropriate
• Explanations: Translated to Korean for better understanding
• Consistency: Maintains same structure and formatting as English version

Fulfills Acceptance Criteria

This PR completes the final acceptance criterion for issue #329:

• ✅ Dependency map with all 7 systems documented (already done in Parts 1-3)
• ✅ Bootstrapper usage guide (already done in Parts 1-3)
• ✅ At least 4 integration scenario examples (already done in Parts 1-3)
• ✅ Error handling across systems explained (already done in Parts 1-3)
• ✅ Initialization/shutdown sequence documented (already done in Parts 1-3)
• ✅ Complete example application with build setup (already done in Parts 1-3)
• ✅ Korean translation created (this PR)

Test Plan

• Korean translation file created and formatted correctly
• All sections from English version included
• Code examples preserved accurately
• Cross-references to English version correct
• No broken links or formatting issues