feat: Complete plugin lifecycle management with lazy loading and runtime reload

Major changes:
- Add unload() method to all plugins for proper cleanup (unregister commands/providers/LSP clients, destroy widgets, clear state)
- Implement lazy widget loading via "show" signal across all containers
- Add autoload: false manifest option for manual/conditional plugin loading
- Add Plugins UI with runtime load/unload toggle via Ctrl+Shift+p
- Implement controller unregistration system with proper signal disconnection
- Add new events: UnregisterCommandEvent, GetFilesEvent, GetSourceViewsEvent, TogglePluginsUiEvent
- Fix signal leaks by tracking and disconnecting handlers in widgets (search/replace, LSP manager, tabs, telescope, markdown preview)
- Add Save/Save As to tabs context menu
- Improve search/replace behavior (selection handling, focus management)
- Add telescope file initialization from existing loaded files
- Refactor plugin reload watcher to dynamically add/remove plugins on filesystem changes
- Add new plugins: file_history, extend_source_view_menu, godot_lsp_client
- Fix bug in prettify_json (undefined variable reference

plugins/code/ui/info_bar/info_bar_widget.py

@@ -35,7 +35,6 @@ class InfoBarWidget(Gtk.Box):
     def _subscribe_to_events(self):
         ...
 
-
     def _load_widgets(self):
         self.path_label      = Gtk.Label(label = "...")
         self.line_char_label = Gtk.Label(label = "1:0")
@@ -92,5 +91,3 @@ class InfoBarWidget(Gtk.Box):
         encoding_type = "utf-8" if not encoding_type else encoding_type
 
         self.encoding_label.set_text(encoding_type)
-
-