SaveManager class

Resource managing save/load operations.

Aggregates state from all Saveable resources and handles file I/O. Save files are stored in the application documents directory, or in SaveConfig.baseDirectory when set.

Save Flow

The save system uses a request pattern to bridge ECS and async I/O:

1. ECS system sets saveRequested when trigger occurs (e.g., sleep, checkpoint)
2. Flutter widget layer checks saveRequested in game loop
3. Widget calls save with current World
4. saveRequested is reset after save completes

Usage

// In ECS system (synchronous)
final saveManager = world.getResource<SaveManager>();
saveManager?.requestSave(metadata: {'playerX': 100, 'playerY': 200});

// In Flutter game loop (async)
if (saveManager.saveRequested) {
  saveManager.clearSaveRequest();
  await saveManager.save(world, 'slot1');
}