refactor(aisidebar): restructure project and implement reasoning mode toggle

- Reorganize project structure and file locations
- Add ReasoningController to manage model selection and reasoning mode
- Update design and requirements for reasoning mode toggle
- Implement model switching between Qwen3-4B-Instruct and Qwen3-4B-Thinking models
- Remove deprecated files and consolidate project layout
- Add new steering and specification documentation
- Clean up and remove unnecessary files and directories
- Prepare for enhanced AI sidebar functionality with more flexible model handling

aisidebar.py

@@ -0,0 +1,73 @@
+from ignis import widgets
+from ignis.window_manager import WindowManager
+from ignis.services.niri import NiriService
+from .chat_widget import ChatWidget
+
+window_manager = WindowManager.get_default()
+
+
+class AISidebar(widgets.RevealerWindow):
+    """AI Chat Sidebar that slides in from the left side"""
+
+    def __init__(self):
+        # Create chat interface
+        self.chat_widget = ChatWidget()
+
+        # Content box - 400px wide to match QuickCenter
+        self.content_box = widgets.Box(
+            vertical=True,
+            spacing=0,
+            hexpand=False,
+            css_classes=["ai-sidebar"],
+            child=[self.chat_widget],
+        )
+        self.content_box.width_request = 400
+        self.content_box.set_halign("start")  # Align to left side
+
+        # Revealer for slide animation
+        revealer = widgets.Revealer(
+            child=self.content_box,
+            transition_duration=300,
+            transition_type="slide_right",  # Slide in from left
+            halign="start",  # Align revealer to left
+        )
+
+        # Close button overlay (click outside to close)
+        close_button = widgets.Button(
+            vexpand=True,
+            hexpand=True,
+            can_focus=False,
+            on_click=lambda x: window_manager.close_window("AISidebar"),
+        )
+
+        main_overlay = widgets.Overlay(
+            css_classes=["popup-close"],
+            child=close_button,
+            overlays=[revealer],
+        )
+
+        super().__init__(
+            revealer=revealer,
+            child=main_overlay,
+            css_classes=["popup-close"],
+            hide_on_close=True,
+            visible=False,
+            namespace="AISidebar",
+            popup=True,
+            layer="overlay",  # Same as QuickCenter
+            kb_mode="exclusive",  # Same as QuickCenter
+            anchor=["left", "right", "top", "bottom"],  # Anchor to ALL edges like QuickCenter
+        )
+
+        self.window_manager = window_manager
+        self.revealer = revealer
+        self.niri = NiriService.get_default()
+
+        self.connect("notify::visible", self._toggle_revealer)
+
+    def _toggle_revealer(self, *_):
+        """Toggle revealer when window visibility changes"""
+        self.revealer.reveal_child = self.visible
+        if self.visible:
+            # Focus on input when opened
+            self.chat_widget.focus_input()