feat(desktop): isolate private data by account

product-source/hololake-native-desktop/src-tauri/src/knowledge_base.rs

@@ -452,22 +452,10 @@ pub async fn select_and_import_knowledge_folder(
 }
 
 fn knowledge_roots(app: &AppHandle) -> Result<(PathBuf, Option<PathBuf>), String> {
-    let native = app
-        .path()
-        .app_data_dir()
-        .map_err(|error| format!("HOLOLAKE_APP_DATA_UNAVAILABLE: {error}"))?
-        .join("knowledge-v1");
+    let native = crate::authenticated_storage::account_storage_root(app, "knowledge-v1")?;
     ensure_native_knowledge_root(&native)?;
-    let legacy = dirs::home_dir()
-        .map(|home| {
-            home.join("Library")
-                .join("Application Support")
-                .join("hololake-desktop")
-                .join("data")
-                .join("knowledge-base")
-        })
-        .filter(|path| path.join("docs").is_dir());
-    Ok((native, legacy))
+    // 旧全局知识库不得自动投影给任一新登录账号；后续只允许用户显式迁移。
+    Ok((native, None))
 }
 
 /// 写私有文件的跨平台选项：unix 上只许本人读写，Windows 上不做额外权限设置。