Instructions per chat (system prompt addition; UI dialog and Telegram /prompt)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

server/src/runner.rs

@@ -293,7 +293,7 @@ pub async fn run_session(app: Arc<App>, session_id: &str, cancel: CancellationTo
         let tools = available_tools(&app, &agent, owner.as_ref());
         let history = active_history(app.store.messages(session_id)?);
         let req = ChatRequest {
-            system: prompts::system_prompt(&app, &agent, &root, &cwd, &model_spec, &session.permission_mode, owner.as_ref()),
+            system: prompts::with_chat_instructions(prompts::system_prompt(&app, &agent, &root, &cwd, &model_spec, &session.permission_mode, owner.as_ref()), &session.instructions),
             messages: history,
             tools: tools.iter().map(|t| t.def()).collect(),
             max_tokens: model.max_output.unwrap_or(16_000),
@@ -704,6 +704,7 @@ fn create_child(app: &Arc<App>, ctx: &ToolCtx, agent_name: &str, description: &s
         pinned: false,
         archived: false,
         folder: None,
+        instructions: String::new(),
     };
     let child = app.save_session(child)?;
     let msg = Message::new(Role::User, vec![Part::Text { text: prompt }]);