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

data/conversations/archive_20251026_073127_5e8a9546.json

@@ -0,0 +1,23 @@
+{
+  "id": "archive_20251026_073127_5e8a9546",
+  "title": "",
+  "created_at": "2025-10-26T07:14:16.661307+00:00",
+  "updated_at": "2025-10-26T07:14:22.827962+00:00",
+  "messages": [
+    {
+      "role": "assistant",
+      "content": "New conversation started. Previous conversation archived.",
+      "timestamp": "2025-10-26T07:14:16.663958+00:00"
+    },
+    {
+      "role": "user",
+      "content": "Test",
+      "timestamp": "2025-10-26T07:14:20.485642+00:00"
+    },
+    {
+      "role": "assistant",
+      "content": "<think>\nOkay, the user just sent \"Test\". I need to respond appropriately. Since it's a simple test, maybe they're checking if I'm active or want to start a conversation. I should acknowledge their message and ask how I can assist them. Keep it friendly and open-ended. Let me make sure the response is clear and invites them to elaborate on what they need help with. Alright, that should cover it.\n</think>\n\nHello! It seems like you're testing me. How can I assist you today? 😊",
+      "timestamp": "2025-10-26T07:14:22.827962+00:00"
+    }
+  ]
+}