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/telescope/telescope.py

@@ -33,6 +33,7 @@ class Telescope(Gtk.Dialog):
     def _setup_signals(self):
         self.connect("focus-out-event", self._focus_out_event)
         self.connect("show", self._show)
+        self.connect("destroy", self._handle_destroy)
 
     def _subscribe_to_events(self):
         ...
@@ -93,7 +94,10 @@ class Telescope(Gtk.Dialog):
         self.source_view.set_buffer(buffer)
 
     def map_parent_resize_event(self, parent):
-        parent.connect("size-allocate", lambda w, r: self._map_resize(self, parent))
+        self.size_allocate_id = parent.connect("size-allocate", lambda w, r: self._map_resize(self, parent))
+
+    def unmap_parent_resize_event(self, parent):
+        parent.disconnect(self.size_allocate_id)
 
     def set_source_view(self, source_view):
         scrolled_win     = Gtk.ScrolledWindow()
@@ -103,3 +107,8 @@ class Telescope(Gtk.Dialog):
         self.main_box.pack_end(scrolled_win, True, True, 0)
 
         scrolled_win.show_all()
+
+    def _handle_destroy(self, widget):
+        self.disconnect_by_func(self._focus_out_event)
+        self.disconnect_by_func(self._show)
+        self.disconnect_by_func(self._handle_destroy)