feat(editor): introduce split pane manager plugin and refactor source view system

* address TODO item for split_pane_manager plugin and bound keys
* add split_pane_manager plugin with create/close split view commands
* move sibling focus/move commands from core into plugin system
* remove legacy toggle_source_view plugin
* redesign EditorsContainer to use simpler Box-based layout
* refactor source view API to return (scrolled_window, source_view)
* add source view lifecycle events (create/remove/removed)
* rename GetNewCommandSystemEvent → CreateCommandSystemEvent
* update CommandsController to support command system creation and cleanup
* ensure command systems are removed with their source views
* improve focus border handling across sibling chains
* update telescope integration for new source view structure
* clean up container imports and initialization logic
* remove old keybindings and align with new split pane workflow

plugins/code/commands/split_pane_manager/plugin.py

@@ -0,0 +1,100 @@
+# Python imports
+
+# Lib imports
+import gi
+
+gi.require_version("Gtk", "3.0")
+
+from gi.repository import Gtk
+
+# Application imports
+from plugins.plugin_types import PluginCode
+
+from libs.event_factory import Event_Factory, Code_Event_Types
+
+from . import create_split_view,    \
+              close_split_view,     \
+              focus_left_sibling,   \
+              focus_right_sibling,  \
+              move_to_left_sibling, \
+              move_to_right_sibling
+
+
+
+class Plugin(PluginCode):
+    def __init__(self):
+        super(Plugin, self).__init__()
+
+
+    def _controller_message(self, event: Code_Event_Types.CodeEvent):
+        ...
+
+    def load(self):
+        gemit_to = self.emit_to
+        self._manage_signals("register_command")
+
+    def unload(self):
+        self._manage_signals("unregister_command")
+
+    def _manage_signals(self, action: str):
+        _create_split_view         = create_split_view
+        _close_split_view          = close_split_view
+        _create_split_view.emit_to = self.emit_to
+        _close_split_view.emit_to  = self.emit_to
+
+        event = Event_Factory.create_event(action,
+            command_name = "create_split_view",
+            command      = _create_split_view,
+            binding_mode = "released",
+            binding      = ["<Control>\\", "<Shift><Control>|"]
+        )
+
+        self.emit_to("source_views", event)
+
+        event = Event_Factory.create_event(action,
+            command_name = "close_split_view",
+            command      = _close_split_view,
+            binding_mode = "released",
+            binding      = "<Shift><Control>w"
+        )
+
+        self.emit_to("source_views", event)
+
+        event = Event_Factory.create_event(action,
+            command_name = "focus_left_sibling",
+            command      = focus_left_sibling,
+            binding_mode = "released",
+            binding      = "<Control>Page_Up"
+        )
+
+        self.emit_to("source_views", event)
+
+        event = Event_Factory.create_event(action,
+            command_name = "focus_right_sibling",
+            command      = focus_right_sibling,
+            binding_mode = "released",
+            binding      = "<Control>Page_Down"
+        )
+
+        self.emit_to("source_views", event)
+
+        event = Event_Factory.create_event(action,
+            command_name = "move_to_left_sibling",
+            command      = move_to_left_sibling,
+            binding_mode = "released",
+            binding      = "<Control><Shift>Up"
+        )
+
+        self.emit_to("source_views", event)
+
+        event = Event_Factory.create_event(action,
+            command_name = "move_to_right_sibling",
+            command      = move_to_right_sibling,
+            binding_mode = "released",
+            binding      = "<Control><Shift>Down"
+        )
+
+        self.emit_to("source_views", event)
+
+    def run(self):
+        ...