Migrate settings storage from XML to JSON with automatic migration

[Copilot]

Changes proposed in this pull request

• Changed settings file format from XML to JSON (Settings.xml → Settings.json)
• Implemented automatic migration on first load with timestamped backups (Settings_[timestamp].xml.backup)
• Added null-safe deserialization for both formats with descriptive exceptions
• Extracted shared JsonOptions configuration (indented, case-insensitive, enum-to-string)
• Refactored error handling in App.xaml.cs to eliminate duplication via HandleCorruptedSettingsFile()

Related issue(s)

N/A

Copilot generated summary

Copilot summary

Migration Logic (SettingsManager.cs):

1. Check for Settings.json → load if exists
2. If not found, check for Settings.xml → deserialize, save as JSON, create timestamped backup
3. If neither exists → initialize defaults

Files Changed:

• SettingsManager.cs: Added JSON serialization, migration logic, shared JsonOptions, null checks
• SettingsInfo.cs: Replaced [XmlIgnore] with [JsonIgnore]
• App.xaml.cs: Added JsonException handler, extracted common recovery logic

Safety:

• Timestamped backups prevent overwriting (Settings_20231223140532.xml.backup)
• Original XML preserved for manual rollback
• Null-safe deserialization throws InvalidOperationException with clear messages
• Corrupted files backed up before reset

JSON Configuration:

private static readonly JsonSerializerOptions JsonOptions = new()
{
    WriteIndented = true,                           // Human-readable
    PropertyNameCaseInsensitive = true,             // Flexible matching
    DefaultIgnoreCondition = JsonIgnoreCondition.Never,  // All properties
    Converters = { new JsonStringEnumConverter() }  // Enums as strings
};

To-Do

• Update documentation to reflect this changes
• Update changelog to reflect this changes

Contributing

By submitting this pull request, I confirm the following:

• I have read and understood the contributing guidelines and the code of conduct.
• I have have added my name, username or email to the contributors list or don't want to.
• The code or resource is compatible with the GNU General Public License v3.0.

Original prompt

can you migrate the NETworkManager.Settings.SettingsManager to use json as new file format. The existing settings files should be automatically migrated to the new file.

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.