Switch AI to Claude and configure Dart import sorting

zed/settings.json

@@ -56,7 +56,7 @@
     "default_profile": "write",
     "model_parameters": [],
     "default_model": {
-      "provider": "copilot_chat",
+      "provider": "zed.dev",
       "model": "claude-sonnet-4"
     },
     "version": "2"
@@ -84,5 +84,16 @@
     "yaml": true,
     "docker-compose": true,
     "golang": true
+  },
+
+  // #############################################
+  // ## Languages                               ##
+  // #############################################
+  "languages": {
+    "Dart": {
+      "code_actions_on_format": {
+        "source.organizeImports": true
+      }
+    }
   }
 }