Passive Skill Trees Fabric

##Skill tree editor command fix

### Fixed
- The `/psteditor` command, which did not match the official syntax documented by the mod author, has been removed.
- `/skilltree editor [treeId]` is now the functional command, compliant with the original FAQ (e.g., `/skilltree editor skilltree:berserker`), and no longer triggers the "Incorrect argument for command" error in-game.

### Changed
- Opening the editor now uses the server command dispatcher (like `reset`, `points`, `grant_skill`) instead of a separate client dispatcher, to avoid a priority conflict between client and server commands sharing the same `skilltree` literal.
- **Behavior change**: `/skilltree editor` now requires operator permission (level 2), just like other `/skilltree` subcommands.
- A new server-to-client network packet (`OpenSkillTreeEditorMessage`) triggers the opening of the editor screen on the client side following command execution on the server side.

### Removed
- The `PSTClientCommands` class (and the `/psteditor` command it registered) has been removed, as it is no longer used.

### Affected files
- `command/PSTCommands.java`
- `command/client/PSTClientCommands.java` *(removed)*
- `network/PSTNetworkChannels.java`
- `network/ServerNetworking.java`
- `network/message/OpenSkillTreeEditorMessage.java` *(new)*
- `client/network/ClientNetworking.java`
- `client/SkillTreeModClient.java`