v5.3.3 - English-only codebase
All user-facing and log messages in the codebase are now in English only (except *_FR.md documentation files).
Web server responses, logs, and comments are fully English.
Version aligned everywhere (platformio.ini, README, CHANGELOG).
See CHANGELOG.md for details.
This release enforces a strict English-only policy for all code and runtime messages, improving internationalization and maintainability.