* 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
- Add `_lsp_java_class_file_contents` request to fetch contents of compiled Java classes via LSP (`java/classFileContents`).
- Handle `java/classFileContents` responses by opening a new buffer with Java syntax highlighting and inserting the returned source.
- Update definition handling to pass URI and range, enabling precise cursor placement after navigation.
- Detect `jdt://` URIs in `textDocument/definition` responses and request class file contents instead of direct navigation.
- Move goto navigation logic into `LSPServerEventsMixin`, using event system to access the active view and position the cursor.
- Expose `emit` and `emit_to` to the response cache for event dispatching.
- Restrict completion activation to `USER_REQUESTED`.
- Add TODO note about mapping language IDs to dedicated response handlers.
- 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
