* Rename legacy controller subsystem (LSPController, websocket controller, controller events, and base classes)
into clarified client module for LSP communication
* Structure around LSPManager and LSPManagerClient to handle orchestration and client lifecycle
* Update plugin integration to use LSPManager instead of LSPController
* Simplify architecture by reducing controller indirection
- Moved prettify_json and lsp_completer plugins to sub categories
- Add filter_out_loaded_files to prevent opening already-loaded files
- Refactor code events into single events module
- Fix signal blocking during file load operations
- Include READONLY state in source view lifecycle handling