fix(mini-app): add app root directory in result_for_assistant

Author: wsp1911

src/crates/core/src/agentic/tools/implementations/miniapp_init_tool.rs

@@ -69,7 +69,7 @@ Input: name, description, icon, category. The tool creates the app directory and
 - manifest (meta.json), source/index.html, source/style.css, source/ui.js, source/worker.js,
   package.json, storage.json.
 
-Returns app_id and absolute paths to each file. Use those paths with Read/Write/Edit to implement the app. The MiniApp uses window.app (app.fs, app.call, app.dialog, etc.) — see miniapp-dev skill for API reference."#
+Returns app_id and the app root directory. Use the root directory and file names above with Read/Write/Edit to implement the app. The MiniApp uses window.app (app.fs, app.call, app.dialog, etc.) — see miniapp-dev skill for API reference."#
             .to_string())
     }
 
@@ -187,8 +187,8 @@ Returns app_id and absolute paths to each file. Use those paths with Read/Write/
         .await;
 
         let result_text = format!(
-            "MiniApp '{}' skeleton created. app_id: {}. Edit the files at the paths below with Read/Write/Edit tools, then open in Toolbox to run.",
-            app.name, app.id
+            "MiniApp '{}' skeleton created. app_id: {}. Root directory: {}. Use Read/Write/Edit tools with files under this root, then open in Toolbox to run.",
+            app.name, app.id, app_dir_str
         );
 
         Ok(vec![ToolResult::Result {