Added

• Added generated file versioning for config.yml, messages.yml, and MySQL.yml.
• Added safe startup/reload updater for generated plugin files.
• Added automatic insertion of missing config/message/database keys from bundled defaults.
• Added backup creation before generated files are changed.

Changed

• Existing user values in generated files are preserved during updates.
• Invalid or missing generated file version values are corrected defensively.
• messages.yml receives missing message keys without overwriting customized messages.

Technical

• Added GeneratedFileVersionUpdater.
• Added configVersion, messagesVersion, and mysqlConfigVersion.
• Generated file backups are written to plugins/betterGraveStones/backups/generated-files/ before modifications.