feat(code): improve comment toggling, terminal navigation, and editor event wiring

- Refactor Commenter toggle logic for line and multi-line comments
  - Preserve indentation and cursor position
  - Improve handling of existing comment detection and removal
  - Simplify bounds vs line comment dispatch

- Enhance terminal project navigation
  - Add project marker detection via Gio file traversal
  - Implement go-to-project-or-home behavior (Home key shortcut)
  - Automatically `cd` into detected project root or home directory
  - Wire terminal widget navigation through VteWidget

- Improve terminal integration
  - Pass emit_to into terminals view for event dispatching
  - Add ability for VteWidget to trigger project navigation

- Update split pane shortcut
  - Change close split view binding to Alt+\

- Add editor event support
  - Emit `text_insert` event from SourceFile on insert
  - Add new TextInsertEvent DTO and register in event system

- Misc cleanup
  - Improve imports and structure in terminals module
  - Add project marker list and filesystem traversal helpers

plugins/code/ui/terminals/vte_widget.py

@@ -122,6 +122,10 @@ class VteWidget(Vte.Terminal):
         ctrl_pressed  = event.state & Gdk.ModifierType.CONTROL_MASK
         shift_pressed = event.state & Gdk.ModifierType.SHIFT_MASK
 
+        if event.keyval == Gdk.KEY_Home:
+            self.go_to_project_or_home()
+            return True
+
         if ctrl_pressed:
             if shift_pressed:
                 if event.keyval in [Gdk.KEY_C, Gdk.KEY_V]: