feat(i18n): add user custom configuration management blog for French locale

Add French translation of the user custom configuration management best practices blog post, covering layered architecture design, core interface design with async operations, configuration data structure with grouped settings, data validation and normalization patterns, DLC feature gating, frontend state management with Redux, concurrency control using SemaphoreSlim, and practical guidelines.

Co-Authored-By: Hagicode <noreply@hagicode.com>
Signed-off-by: newbe36524 <newbe36524@qq.com>

Author: newbe36524