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/markdown_preview/manifest.json

@@ -3,5 +3,6 @@
     "author": "ITDominator",
     "version": "0.0.1",
     "support": "",
+    "autoload": false,
     "requests": {}
 }

plugins/code/ui/markdown_preview/markdown_preview.py

@@ -7,6 +7,7 @@ gi.require_version('Gdk', '3.0')
 
 from gi.repository import Gtk
 from gi.repository import Gdk
+from gi.repository import GLib
 
 # Application imports
 from core.widgets.webkit.webkit_ui import WebkitUI
@@ -47,6 +48,7 @@ class MarkdownPreview(Gtk.Popover, MarkdownPreviewMixin):
     def _setup_signals(self):
         self.connect("hide", self._handle_hide)
         self.connect("show", self._handle_show)
+        self.connect("destroy", self._handle_destroy)
 
     def _load_widgets(self):
         box             = Gtk.Box()
@@ -71,7 +73,6 @@ class MarkdownPreview(Gtk.Popover, MarkdownPreviewMixin):
         box.set_orientation(Gtk.Orientation.VERTICAL)
 
         self.start_stop_bttn.connect("clicked", self._tggle_preview_updates)
-        settings_bttn.connect("clicked", self._handle_settings)
 
         bttn_box.pack_end(self.start_stop_bttn, expand = False, fill = False, padding = 1)
         bttn_box.pack_end(settings_bttn, expand = False, fill = False, padding = 1)
@@ -98,5 +99,8 @@ class MarkdownPreview(Gtk.Popover, MarkdownPreviewMixin):
     def _tggle_preview_updates(self, widget):
         self.is_preview_paused = not self.is_preview_paused
 
-    def _handle_settings(self, widget):
-        ...
+    def _handle_destroy(self):
+        self.disconnect_by_func(self._handle_hide)
+        self.disconnect_by_func(self._handle_show)
+        self.disconnect_by_func(self._handle_destroy)
+        self.start_stop_bttn.disconnect_by_func(self._tggle_preview_updates)

plugins/code/ui/markdown_preview/plugin.py

@@ -51,6 +51,18 @@ class Plugin(PluginCode):
 
         self.emit_to("source_views", event)
 
+    def unload(self):
+        event = Event_Factory.create_event("unregister_command",
+            command_name = "tggle_markdown_preview",
+            command      = Handler,
+            binding_mode = "released",
+            binding      = "<Shift><Control>m"
+        )
+
+        self.emit_to("source_views", event)
+
+        markdown_preview.destroy()
+
     def run(self):
         ...
 
@@ -67,4 +79,14 @@ class Handler:
         if not markdown_preview.can_hide:
             markdown_preview.can_hide = True
 
-        markdown_preview.popdown() if markdown_preview.is_visible() else markdown_preview.popup()
+        if markdown_preview.is_visible():
+            markdown_preview.popdown()
+            return
+
+        file   = view.command.exec("get_current_file")
+        if not file or not file.get_location(): return
+        buffer = view.get_buffer()
+
+        markdown_preview.popup()
+        markdown_preview.fpath = file.get_location().get_path()
+        markdown_preview._do_markdown_translate(buffer)