CoreChatX Config Manager Changes

Added

• Added automatic default-key synchronization for Paper YAML configuration files.
• When a config file exists but is missing a key from the bundled default, CoreChatX now writes that missing key back into the real file.
• Existing configured values are preserved and are not overwritten by bundled defaults.
• Missing nested sections and empty map sections are restored, including values such as route maps and channel overrides.
• The default locale file locales/en_us.yml is also synchronized from bundled defaults.
• Velocity velocity-config.properties now appends missing bundled default properties when the file exists but is incomplete.

Safety Rules

• Invalid or unparsable YAML files are not rewritten automatically.
• Runtime data files such as playerdata.yml, state.yml, channeldata.yml, ignoredata.yml, and mutedata.yml are not treated as normal admin config for default-key synchronization.
• Velocity properties are appended instead of rewriting the whole file, so existing comments and values stay intact.

Technical

• Added DefaultConfigSynchronizer as the Paper-side central YAML loader/synchronizer.
• Updated Paper config loading paths to use the synchronizer through ConfigurationService, ConfigRegistry, and the default locale loader.
• Added regression coverage for restoring missing nested defaults without overwriting existing values.
• Added missing-property synchronization to the Velocity bootstrap config loader.