feat: first cut at dev brain

src/app/projects.rs

@@ -152,6 +152,7 @@ impl App {
                 self.project_name_input.clear();
                 self.error = None;
                 self.reload_projects();
+                self.invalidate_dev_brain_context();
                 self.refresh_git_state();
             }
             Err(error) => self.error = Some(error),
@@ -349,6 +350,21 @@ impl App {
             }
         }
     }
+
+    pub(super) fn invalidate_dev_brain_context(&mut self) {
+        if !self.config.dev_brain.enabled {
+            return;
+        }
+        #[cfg(target_os = "macos")]
+        {
+            self.agent_tools = None;
+            for chat in self.background_chats.values_mut() {
+                chat.agent_tools = None;
+                chat.system_prompt_seen_at = 0;
+            }
+        }
+        self.system_prompt_seen_at = 0;
+    }
 }
 
 fn read_git_state(path: &Path) -> Option<GitState> {