Fix: Properly re-register capabilities after plugin hot reload

[SlynxCZ]

Hi! This change makes sure that plugin capabilities get correctly re-registered after a hot reload.

Previously, when a plugin reloaded, its registered capability delegates (like PlayerCapability<T> or PluginCapability<T>) could still point to the old assembly context, which got unloaded right after. That meant other plugins were sometimes trying to call outdated or invalid delegates — leading to weird behavior or occasional crashes. 😅

Now, during hot reload, the plugin will:

1. Unregister all old capabilities
2. Rebuild new supplier delegates (using Expression.Lambda)
3. Re-register them automatically for the fresh plugin instance

This keeps all providers up-to-date and prevents dangling references to old assemblies.
Overall, it just makes the capability system more stable and consistent when doing frequent plugin reloads. 👍